1- Choice D is correct
The correct answer is N \ + \ 4 Mary has N books. Lucy has 7 more books than Mary. Then, Lucy has N \ + \ 7 books. If Lucy gives Mary 3 books, Lucy will have: N \ + \ 7 \ - \ 3 = N \ + \ 4
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2- Choice B is correct
The correct answer is 90 If 20 percent of a number is 45, then the number is: 20\% of x = 45 → 0.20 = 40 → x= \frac{45}{0.20} = 225 45 percent of 225 is: 40\% of 225 = \frac{40}{100} \times 225 = 90
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3- Choice C is correct
The correct answer is 12 If \frac{5 \ x}{2} = 40, then: 5 \ x = 80 → x = 16 \frac{3 \ x}{4} = \frac{3 \times 16}{4} = \frac{48}{4} = 12
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4- Choice A is correct
The correct answer is \frac{5}{15} \times 3 0.2 \times 2 = 0.4, all options provided are equal to 0.4 except option A. \frac{5}{15} \times 3 = 1
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5- Choice C is correct
The correct answer is 0.2 \ × \ 30 = 6 \frac{1}{5} of 30 is 6. Let’s review the options provided: A. 0.3 \ ×\ 6 = 1.8 B. 0.3 \ ×\ 5 = 1.5 C. 0.2 \ × \ 30 = 6 D. 0.2 \ × \ 35 = 7 E. 0.2 \ × \ 39.5 = 7.9
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6- Choice E is correct
The correct answer is 30 The sum of supplement angles is 180. Let x be that angle. Therefore, x \ + \ 5\ x = 180 6\ x = 180, divide both sides by 6: \ x = 30
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7- Choice A is correct
The correct answer is 160 degrees x = 30 \ +\ 130 = 160 degrees
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8- Choice D is correct
The correct answer is 40\% Use the formula for Percent of Change \frac{New \ Value-Old \ Value}{Old \ Value} \times 100\% \frac{18 \ -\ 30}{30} \times 100\% = \ – \ 40\% (negative sign here means that the new price is less than old price)
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9- Choice B is correct
The correct answer is 264 cm^2 The perimeter of the trapezoid is 60. Therefore, the missing side (height) is: = 60 \ – \ 16 \ – \ 12 \ – \ 10 = 22 Area of the trapezoid: A = \frac{1}{2} \ h \ (b1 \ + \ b2) = \frac{1}{2} \ (22) \ (12 \ + \ 10) =264
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10- Choice B is correct
The correct answer is 32 The diagonal of the square is 8. Let x be the side. Use Pythagorean Theorem: a^2 \ +\ b^2 = c^2 x^2 \ + \ x^2 = 8^2 ⇒ 2 \ x^2 = 8^2 ⇒ 2 \ x^2 = 64 ⇒ x^2 = 32 ⇒ x= \sqrt{32} The area of the square is: \sqrt{32} \times \sqrt{32} = 32
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11- Choice A is correct
The correct answer is 7 Simplify and solve for x in the equation. 3 \ (x \ + \ 2) = 2 \ (x \ − \ 6) \ + \ 24 → 3 \ x \ + \ 6 = 2 \ x \ − \ 12 \ + \ 24 3 \ x \ + \ 3 = 2 \ x \ – \ 12 Subtract 2 \ x from both sides: x \ + \ 3 = – \ 4, Add 4 to both sides: x = 7
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12- Choice E is correct
The correct answer is 10 If the score of Ashly was 40, therefore the score of Jennifer is 20. Since, the score of Ashly was half as that of Jennifer, therefore, the score of Ashly is 10.
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13- Choice A is correct
The correct answer is 5 Let x be the number. Then: 4 \ x \ +\ 4=24 Solve for x: \ 4 \ x \ + \ 4 =24→ 4 \ x=24 \ - \ 4=20→ x=20 \div 4=5
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14- Choice E is correct
The correct answer is 28 Five years ago, Emily was three times as old as John. John is 12 years now. Therefore, 5 years ago John was 7 years. Five years ago, Emily was: A = 3 \times 7=21 Now Emily is 28 years old: 21 \ +\ 7 = 28
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15- Choice B is correct
The correct answer is 14 Let x be the number. Write the equation and solve for x. \frac{1}{3} \times 12= \frac{2}{7}. x ⇒ \frac{1 \times 12}{3} = \frac{2 \ x}{7} , use cross multiplication to solve for x. 12 \times 7 = 2 \ x \times 3 ⇒ 84 = 6 \ x ⇒ x = 14
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16- Choice C is correct
The correct answer is $\ 10 Let x be one-kilogram orange cost, then: 3 \ x \ + \ (2 \ × \ 3.2) = 36.4 → 3 \ x \ + \ 6.4 = 36.4 → 3 = 36.4 \ - \ 6.4 → 3 \ x = 30 → x=\frac{30}{3} = $\ 10
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17- Choice B is correct
The correct answer is 3 Let x be the number. Write the equation and solve for x. (18 \ – \ x) \ ÷ \ x = 6 Multiply both sides by x. (18 \ – \ x) = 6 \ x, then add x both sides. 18 = 6 \ x, now divide both sides by 6. x = 3
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18- Choice A is correct
The correct answer is 60.66 average = \frac{sum \ of \ terms}{number \ of \ terms} The sum of the weight of all girls is: 12 \ ×\ 54 = 648 kg The sum of the weight of all boys is: 24 \ × \ 64 = 1,536 kg The sum of the weight of all students is: 648\ + \ 1,536 = 2,184 kg Average = \frac{2,184}{36} = 60.66
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19- Choice C is correct
The correct answer is 21 In a group of 3 books, the average number of pages is 20. Therefore, the sum of pages in all 3 books is (3 \ × \ 20 = 54). Ava adds a book with 24 pages to the group. Then, the sum of pages in all 4 books is: (3 \ × \ 20 \ +\ 24 =84 ). The new average number of pages per book is: \frac{84}{4}=21
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20- Choice E is correct
The correct answer is 6 Solve for x in the equation. 3(x \ +\ 2) = 24→ 3 \ x \ + \ 6=24→ 3 \ x=24 \ - \ 6=18→ x = 18 \div 3=6
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21- Choice D is correct
The correct answer is \frac{2}{3} \ > \ 0.6 Only option D is correct. \frac{2}{3} =0.66→ 0.6 \ < \ \frac{2}{3}
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22- Choice A is correct
The correct answer is 14 \frac{2}{3} \ × \ 21= \frac{42}{3} =14
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23- Choice B is correct
The correct answer is 100 cm One lite =1000 cm^{3} → 4 liters = 4,000 cm^{3} 4,000=10 \times 4 \times h → h =\frac{4000}{4}=100 cm
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24- Choice B is correct
The correct answer is 35 Choices A, C, D, and E are incorrect because 80\% of each of the numbers is a non-whole number. A. 49 80\% of 49 = 0.80 \ × \ 49=39.2 B. 35 80\% of 35=0.80 \ × \ 35=28 C. 32 80\% of 32=0.80 \ × \ 32=25.6 D. 12 80\% of 12=0.80 \ × \ 12=9.6 E. 8 80\% of 8=0.80 \ × \ 8=6.4
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25- Choice B is correct
The correct answer is 25 The red box is 30\% greater than the blue box. Let x be the capacity of the blue box. Then: x \ + \ 30\% of x=50→ 1.3 \ x=50→ x=\frac{50}{1.3}=25
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25- Choice B is correct
The correct answer is 25 The red box is 30\% greater than the blue box. Let x be the capacity of the blue box. Then: x \ + \ 30\% of x=50→ 1.3 \ x=50→ x=\frac{50}{1.3}=25
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26- Choice A is correct
The correct answer is \frac{1}{6} From the options provided, only C (\frac{1}{6}) is less than \frac{1}{3}.
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27- Choice C is correct
The correct answer is 18 Four people can paint 5 houses in 15 days. It means that for painting 10 houses in 6 days we need 9 people. To paint 10 houses in 6 days, 18 people are needed.
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28- Choice D is correct
The correct answer is $\ 48 $\ 10 \ × \ 8=$\ 80 Petrol use: 8 \ × \ 2=16 liters Petrol cost: 16 \ × \ $\ 2=$\ 32 Money earned: $\ 80 \ -\ $\ 32=$\ 48
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29- Choice E is correct
The correct answer is 3 N \ × \ (6 \ -\ 3)=9→ N \ ×\ 3=9→ N=3
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30- Choice A is correct
The correct answer is $\ 4.69 Ann earns $20.00 per hour now. $20.00 per hour is 15 percent more than her previous rate. Let x be her rate before her raise. Then: x \ +\ 0.15 \ x=20→ 1.15 \ x=20→ x=\frac{20}{1.15}=17.39 Alex earns $25.40 per hour now. $25.40 per hour is 15 percent more than his previous rate. Let x be Alex’s rate before his raise. Then: x \ + \ 0.15 \ x=25.40→ 1.15\ x=25.40→ x=\frac{25.40}{1.15}=22.08 Ann earned $\ 4.69 more per hour than John before their raises.
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31- Choice C is correct
The correct answer is 50^° \alpha =180^° \ -\ 105^°=75^° \beta =180^° \ - \ 125^°=55^° The sum of all angles in a triangle is 180 degrees. Then: x \ + \ \alpha \ + \ \beta= 180^°→x=180^° \ - \ 75^° \ - \ 55^°=50^°
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32- Choice B is correct
The correct answer is 9 The width of a rectangle is 2 \ x and its length is 3 \ x. Therefore, the perimeter of the rectangle is 10 \ x. Perimeter of a rectangle =2(width + length) =2 \ (2 \ x \ + \ 3\ x)=2 \ (5\ x)=10\ x The perimeter of the rectangle is 90. Then: 10 \ x=90→x=9
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33- Choice A is correct
The correct answer is 0.01 0.35 equals 35M. Then: 35 M =0.35→ M = \frac{0.35}{35}=0.01
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34- Choice C is correct
The correct answer is 40 The length of the rectangle is 16. Then, its width is 4. 16 \ ÷ \ 4 = 4 Perimeter of a rectangle = 2 \ × width + \ 2\ × length =2 \ × \ 4 \ + \ 2 \ × \ 16= 8 \ + \ 32=40
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35- Choice A is correct
The correct answer is 24 If x∎y=4 \ x \ + \ y \ - \ 3, Then: 3∎15=4(3) \ + \ 15 \ -\ 3=12 \ + \ 15 \ - \ 3=24
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36- Choice E is correct
The correct answer is 6 \ x \ +\ 17 z=2 \ x \ + \ 5, then: 3 \ z=3(2 \ x \ + \ 5)=6 \ x \ + \ 15 3 \ z \ + \ 2=6 \ x \ +\ 15 \ + \ 2= 6 \ x \ +\ 17
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37- Choice B is correct
The correct answer is 25 \frac{1}{8} =0.125→ C =5 \frac{1}{20}=0.05→ D =5→ C \times D =5 \ ×\ 5=25
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38- Choice D is correct
The correct answer is x \ × \ 4 36=x \ × \ 4→ x=36 \ ÷ \ 4=9 x equals to 9. Let’s review the options provided: A. x \ +\ 3→ 9 \ +\ 4=13 36 is not divisible by 13. B. 2 \ x \ + \ 10→2 \ ×\ 9 \ + \ 10=28 36 is not divisible by 28. C. x \ - \ 16→9 \ -\ 16=7 36 is not divisible by 7. D. x \ × \ 4→9 \ × \ 4=36 36 is divisible by 36. E. x \ + \ 1→9 \ +\ 1=10 36 is not divisible by 10.
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39- Choice A is correct
The correct answer is 12 The area of the floor is: 4 cm \times \ 18 cm =72 cm The number is tiles needed = 72\div 6 = 12
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40- Choice E is correct
The correct answer is - \ 14 Use cross product to solve for x. \frac{x}{x \ - \ 4}= \frac{2}{3}→ 3 \ × \ x=2 \ × \ (x \ - \ 4)→ 3 \ x=2 \ x \ - \ 8= - \ 8→ x \ - \ 6= - \ 8\ - \ 6= - \ 14
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41- Choice A is correct
The correct answer is \frac{1}{9} Number of biology book: 20, total number of books; 20 \ +\ 85 \ + \ 75=180 the ratio of the number of biology books to the total number of books is: \frac{20}{180}=\frac{1}{9}
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42- Choice D is correct
The correct answer is $\ 675 Let x be all expenses, then: \frac{20}{100} \ x=$\ 500 → x=\frac{100 \ × \ $\ 500}{20}=$\ 2500 He spent for his rent: \frac{27}{100} \ × \ $\ 2500=$\ 675
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43- Choice B is correct
The correct answer is 0.2 \ x \ +\ 5,000 x is the number of all sales profit and 2\% of it is: 2\% \ × \ x=0.02 \ x Employee’s revenue: 0.2 \ x \ +\ 5,000
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44- Choice A is correct
The correct answer is 1,650 4,000 \ + \ A \ - \ 250=5,400→ 4,000 \ +\ A=5,400 \ + \ 250 \ =5,650→ A=5,650 \ - \ 4,000=1,650
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45- Choice A is correct
The correct answer is \frac{1}{4} 4 \ ×\ M\ + \ 6=7→ 4 \ × \ M=7 \ -\ 6=1→ M=\frac{1}{4}
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46- Choice B is correct
The correct answer is 5 The angles on a straight line add up to 180 degrees. Then: x \ +\ 55 \ + \ y \ + \ 2 \ x \ +\ y=180 Then: 3 \ x \ + \ 2 \ y=180 \ -\ 55→ 3(45) \ + \ 2 \ y=125→ 2 \ y=135 \ -\ 125=10→ y=5
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47- Choice C is correct
The correct answer is 98 The ratio of lions to tigers is 6 to 3 at the zoo. Therefore, total number of lions and tigers must be divisible by 9. 6 \ + \ 3=9 From the numbers provided, only 98 is not divisible by 9.
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48- Choice D is correct
The correct answer is 0.524 \frac{52.4}{100}=0.524
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49- Choice A is correct
The correct answer is 33 let x be the number of gallons of water the container holds when it is full. Then: \frac{3}{21} \ x=4.5→ x=\frac{21 \ × \ 4.5}{3}=33
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50- Choice B is correct
The correct answer is Greater than 5 If x is greater than 15, then \frac{1}{3} of x must be greater than: \frac{1}{3} \ × \ 15=5.
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