If A can do a piece of work in n days, then A’s 1 days work = 1/n
If A’s 1 day work = 1/n , then A can finish the work in n days
1. A is twice as good as workman as B and together they finish a piece of work in 18 days .In how many days will A alone finish the work
(A’s 1 days work ): (B’s 1 days work) = (2: 1)
(A+B)’s 1 day work = 1/18
A’s 1 days work = (1/18 * 2/3) = 1/27
Hence A alone can finish the work in 27 days
2.A can do a certain job in 12 days. B is 60 % more efficent than A .How many days B alone take to the same job ?
Ratio of time taken by A and B = 160 : 100 = 8 : 5
Suppose B alone takes x days to do the job
Then 8 : 5 : : 12 : x => 8x = 5 * 12 => x = 7 1/ 2 days
3.10 men can complete a piece of work in 15 days and 15 women can complete the same work in 12 days . If all the 10 men and 15 women work together , in how many days will the work get completed ?
10 men’s 1 day’s work = 1/15
15 women’s 1 day’s work = 1/12
(10 men + 15 women ) 1 days work = (1/15+ 1/12) = 9/60 = 3/20
10 men and 15 women will complete to work in 3/30 = 6 6/3 days
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