Varun alone can do a work in 10 days, whereas Ganesh can do the same work in 25 days. If they both are working on

Varun alone can do a work in 10 days, whereas Ganesh can do the same work in 25 days. If they both are working on alternate days starting with Varun, then find the total time taken to complete the work.

a)            16.4 days

b)            20.5 days

c)            14.2 days

d)            24 days

e)            12.6 days

 Sol:

Let total of work = 50 units (LCM of (10, 25))

Efficiency of Varun = (50/10) = 5 units/day

Efficiency of Ganesh = (50/25) = 2 units/day

Work done by Varun and Ganesh together in 2

days = 5 + 2 = 7 units

Amount of work done by Varun and Ganesh

together in 7 days = 7 × 7 = 49 units

Time taken by Varun to complete remaining work

= 1/5 = 0.2 days

Total time taken to complete the work = 14 + 0.2

= 14.2 days.