Time and work
Top questions
See all →- 12 men or 18 women can complete a piece of work in 14 days. In how many days will 8 men and 16 women together complete the same work? Answer: D. 9 days Answer: (D) 9 days 12 men = 18 women, so 1 man = 1.5 women. 8 men + 16 women = 12 + 16 = 28 women. Work = 18 × 14 = 252 wo... 1
- A can do a piece of work in 16 days and B can do it in 24 days. They work together for 6 days and then A leaves. In how many more days will B finish the remaining work? Answer: B. 9 days Answer: (B) 9 days In 6 days together: 6(1/16 + 1/24) = 6 × 5/48 = 5/8 . Remaining 3/8 ; B needs 3/8 × 24 = 9 days. 1
- A and B together can finish a work in 12 days, B and C in 15 days, and C and A in 20 days. In how many days can A, B and C together finish it? Answer: C. 10 Answer: (C) 10 2(A + B + C) = 1/12+1/15+1/20 = 12/60 = 1/5 . So A + B + C = 1/10 : 10 days. 1
- A can finish a work in 12 days and B in 18 days. They work together for 4 days, after which A leaves. In how many more days will B finish the remaining work? Answer: D. 8 Answer: (D) 8 In 4 days they do 4(1/12+1/18) = 5/9 . Remaining 4/9 at B's rate 1/18 takes 8 days. 1
- A can finish a piece of work in 12 days and B in 18 days. How many days will they take working together? Answer: D. 7.2 days Answer: (D) 7.2 days Shortcut: together = ab/a+b = 12 × 18/30 = 7.2 days. LCM method: work = 36 units; A does 3/day, B 2... 1
- 15 men can finish a job in 20 days. How many days will 25 men take to finish the same job? Answer: D. 12 days Answer: (D) 12 days Shortcut: M₁D₁ = M₂D₂. 15 × 20 = 25 × D, so D = 12 days. 1