1) Ramesh can complete a work in 12 days, working 7 hours a day. Suresh can complete the same work in 8 days, working 9 hours a day. If Ramesh and Suresh work together working 7 hours a day, in how many days can they complete the work?
a. 7 * 3 / 23
b. 5 * 7 / 13
c. 6 * 5 / 13
d. 6 * 6 / 11
e. None of these
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Answer
Explanation
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ANSWER: 5 * 7 / 13
Explanation:
Ramesh can finish the work in 12 * 7 = 84 hours
Amount of work he can complete in 1 hour = 1/84
Suresh can finish the same work in 8 * 9 = 72 hours
Amount of work he can complete in 1 hour = 1/72 hours
Work done by both of them in 1 hour =
= 1/84 + 1/72 = 13/504
Ramesh and Suresh together can complete the work in 504/13 hours.
i.e. 504/13 * 1/7 = 72/13 days
i.e. 5 * 7 / 13 days
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2) If 500 gm of salt solution has 30% salt in it, how much salt must be added to make the concentration of salt 50% in the solution?
a. 200 gm
b. 100 gm
c. 90 gm
d. 50 gm
e. None of these
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Answer
Explanation
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ANSWER: 200 gm
Explanation:
Amount of water in solution = 100 % - 30 % = 70 % of total
Amount of water = 70 % x 500 = 350 gm
Amount of water remains same for both the solutions. Therefore, let amount of new solution be x gm.
x = 350 x (100/ 50)
x = 700
Salt added = (700 – 500) = 200 gm
Alternate solution:
Quantity of sugar to be added :
= [Solution (Required % value – Present % value)] / (100 – Required % value)
= [500 (50 – 30)] / 100 – 50
= (500 x 20) / 50
= 200 gm
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3) The L.C.M. Of 2, 2.7 and 0.09 is:
a. 5.4
b. 0.54
c. 0.054
d. 54
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Answer
Explanation
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ANSWER: 54
Explanation:
Given numbers are 2.00, 2.70 and 0.09.
L.C.M. of 200, 270 and 9 is 5400.
L.C.M. Of given numbers = 54.00 = 54
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4) Which of the following fraction is greater than 2/3 and less than 4/5 ?
a. 1/2
b. 9/10
c. 3/4
d. 5/6
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Answer
Explanation
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ANSWER: 3/4
Explanation:
1/2 = 0.5, 2/3 = 0.66, 4/5 = 0.8, 9/10 = 0.9, 3/4 = 0.75, 5/6 = 0.833,
Clearly, 0.8 lies between 0.75 and 0.833
3/4 lies between 2/3 and 4/5
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5) 3/8 of 168 * 15 / 5 + X = 549 / 9 + 275
a. 107
b. 147
c. 10
d. 296
e. None of these
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Answer
Explanation
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ANSWER: 147
Explanation:
Let 3/8 of 168 * 15 / 5 + X = 549 / 9 + 275
Then, 63 * 15 / 5 + X = 61 + 275
63 * 3 + X = 336
189 + X = 336
X = 147
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6) The average of five consecutive odd numbers is 51. What is the difference between the highest and lowest number?
a. 3
b. 7
c. 8
d. 11
e. None of these
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Answer
Explanation
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ANSWER: 8
Explanation:
Let the numbers be x, x + 2, x + 4, x + 6 and x + 8.
Then, [x + (x + 2) + (x + 4) + (x + 6) + (x + 8)] / 5 = 51
5x + 20 = 255
x = 47
So, required difference = (47 + 8) – 47 = 8
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7) If the sum of a number and its square is 272, What is the number?
a. 14
b. 16
c. 19
d. 21
e. None of these
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Answer
Explanation
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ANSWER: 16
Explanation:
Let the integer be x.
Then, x + x2 = 272
x2 + x - 272 = 0
(x + 17) (x – 16) = 0
x = 16
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8) The present ages of three persons are in proportions 4 : 7 : 9. Eight years ago, the sum of their ages was 76. Find their present ages (in years).
a. 8, 20, 28
b. 12, 21, 27
c. 20, 35, 45
d. None of these
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Answer
Explanation
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ANSWER: 20, 35, 45
Explanation:
Let their present ages be 4x, 7x and 9x years respectively.
Then, (4x – 8) + (7x – 8) + (9x – 8) = 76
20x = 100
x = 5
Their present ages are 20 years, 35 years and 45 years respectively.
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9) If 5a = 625, then the value of 5(a – 2) is:
a. 5
b. 25
c. 125
d. 625
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Answer
Explanation
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ANSWER: 25
Explanation:
5a = 625
5a = 54
a = 4
Therefore,
5(a – 2) = 5(4 – 2) = 52 = 25
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10) The number which exceeds 12% of it by 52.8 is:
a. 50
b. 52
c. 58
d. 60
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Answer
Explanation
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ANSWER: 60
Explanation:
Let the number be x. Then, x – 12% of x = 52.8
x – (12/100)x = 52.8
x (1– 12/100) = 52.8
(88/100)x = 52.8
x = (100 X 52.8) / 88 = 60
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