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Aptitude & Reasoning · Question Set
Time & Work, Pipes & Cisterns interview questions for placements and exams.
Questions
14
Included in this set
Subject
Aptitude & Reasoning
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Difficulty
Mixed
Level of this set
Go through each question and its explanation. Use this set as a focused practice pack for Aptitude & Reasoning.
Add daily work. One by fifteen plus one by twenty equals seven by sixty per day. Time equals sixty by seven days, which is eight and four sevenths.
1/T = 1/15 + 1/20 = 7/60 ⇒ T = 60/7
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Fifty percent more efficient means time becomes two thirds. Two thirds of twelve equals eight days.
T_B = 12 ÷ 1.5 = 8
Total rate is one by twelve. Subtract B’s one by thirty six to get A’s one by eighteen. So A takes eighteen days.
1/A = 1/12 − 1/36 = 1/18
Net rate is one by six plus one by eight minus one by twelve equals five by twenty four tank per hour. Time is twenty four by five which is four hours forty eight minutes.
1/T = 1/6 + 1/8 − 1/12 = 5/24 ⇒ T = 24/5
In two days, work done is one by eighteen plus one by twenty seven equals five by fifty four. After 20 days (10 pairs), work done is fifty by fifty four. Day 21 by A adds three by fifty four, leaving one by fifty four. B needs half a day more. Total is 21.5 days.
After 20d: 50/54; +A: 53/54; remaining 1/54 ⇒ B needs (1/54)/(1/27)=0.5 d
A rate is one by twelve. B rate is one by eight minus one by twelve equals one by twenty four. In 3 days together they complete three by eight. Remaining is five by eight. B takes (5/8)/(1/24) equals 15 days.
Remain = 1 − 3/8 = 5/8 ⇒ t = (5/8)/(1/24) = 15
Net rate is one by three plus one by six minus one by nine equals seven by eighteen tank per hour. Time is eighteen by seven hours, about two hours thirty four minutes.
1/T = 1/3 + 1/6 − 1/9 = 7/18 ⇒ T = 18/7
Net rate is one by ten minus one by thirty equals one by fifteen tank per hour. So time is fifteen hours.
1/T = 1/10 − 1/30 = 1/15 ⇒ T = 15
Shares follow efficiency. B gets two fifths of two thousand five hundred which is one thousand.
Share_B = (2/5)×2500 = 1000
Men are inversely proportional to time. Required equals twelve times fifteen over nine equals twenty men.
m₂ = 12×15/9 = 20
From 3 men = 5 women, one man equals five thirds women. So 6 men + 10 women equals 20 women. Since 5 women take 24 days, total work is 5w×24. Time with 20w is (5w×24)/(20w) = 6 days.
T = (5w×24)/(20w) = 6
Take LCM 30 units. A does 3 units per day. In 2 days A does 6 units. Remaining is 24 units. B does 2 units per day, so needs 12 days.
Remain = 30 − 2×3 = 24 ⇒ 24/2 = 12
Use 60-unit work. Rates are 3 and 2 units per minute. First 5 min add 25 units. Remaining 35 units are filled by the second at 2 per minute, taking 17.5 min. Total is 22.5 min.
Work = 25 + 2t = 60 ⇒ t = 17.5 ⇒ total 22.5
Use 60 units as total work. Rates: 5 and 4 units per minute. Let x be minutes when both are open. Then 9x + 4(10 − x) = 60. Solve to get x = 4 minutes.
9x + 40 − 4x = 60 ⇒ 5x = 20 ⇒ x = 4