Aptitude Day 234

Problems on Time and Work:

1. A works twice as fast as B. If B can complete a work in 6 days independently, the number of days in which both can finish the work is:

Solution:

                  Their ratio will be 2: 1

                   Their 1 day’s work = (1/3 + 1/6) = 1/3

                   They can together finish the work in 3 days.

2. A is 50% more efficient than B. How much time will they, working together, take to complete a job which A alone could have done in 12 days?

Solution:

                  Let B takes x days to do a work.

                  Time taken by both in ratio = 100: 150 :: 12: x

                  x = 18.

                  Their 1 day’s work = 1/12 + 1/18 = 5/36.

                  They take 1(5/36) days to complete the work which is 7(1/5) days.