


8.
A and B undertake to do a piece of work for Rs.600. A alone can do it in 6 days while B alone can do it in 8 days. With the help of C, they finish it in 3 days. Find the share of each.
9.
A and B working separately can do a piece of work in 9 days and 12 days respectively. If they work for a work alternately, A beginning, in how many days, the work will be completed?
Answer & Solution
Answer: b) 10 1/4 days
Solution: (A + B)'s 2 day's work = (1/9 + 1/12) = 7/36 Work done in 5 pairs of days = [5 * (7/36)] = 35/36 Remaining work = [1  (35/36)] = 1/36 On 11th day, it is A's turn. 1/9 work is done by him in 1 day. 1/36 work is done by him in [9 * (1/36)] = 1/4 days. Total time taken = [10 + (1/4 )] days = 10 1/4 days 10.
45 men can complete a work in 16 days. Six days after they started working, 30 more men joined them. How many days will they now take to complete the remaining work?
Answer & Solution
Answer: c) 6 days
Solution: (45 * 16) men can complete the work in 1 day. 1 man's 1 day's work = 1/720 45 men's 6 day's work = [(1/16) * 6] = 3/8 Remaining work = [1  3/8] = 5/8 75 men's 1 day's work = 75/720 = 5/48 Now, 5/48 work is done by them in 1 day. 5/8 work is done by them in [(48/5) * (5/8)] = 6 days. 11.
2 men and 3 boys can do a piece of work in 10 days while 3 men and 2 boys can do the same work in 8 days. In how many days can 2 men and 1 boy do the work?
Answer & Solution
Answer: c) 12 1/2 day
Solution: Let 1 man's 1 day's work = x and 1 boy's 1 day's work = y Then, 2x + 3y = 1/10 and 3x + 2y = 1/8 Solving, we get: x = 7/200 and y = 1/100 (2 man + 1 boy)'s 1 day's work = [2 * (7/200) + 1 * (1/100)] = 16/200 = 2/25 So, 2 men and 1 boy together can finish the work in 25/2 = 12 1/2 days. 12.
A does a work in 10 days and B does the same work in 15 days. In how many days they together will do the same work? [R.R.B. 2003]
13.
A an finish a work in 18 days and B can do the same work in half the time taken by A. Then, working together, what part of the same work they can finish in a day? [S.S.C 2002]
14.
A tyre has two punctures. The first puncture alone would have made the tyre flat in 9 minutes and the second alone would have done it in 6 minutes. If air leaks out at a constant rate, how long does it take both the punctures together to make it flat? D.M.R.C 2003]
