Question

a and b together can complete a task in 12 days.however if a works alone, completes half the job and leaves and then b works alone and completes the rest of the work,it takes 25 days in all to complete the work.of b i more efficient than a,how many days it would have taken b to do the work by himself to

Answer 1

let task be x

a and b can do work in 12 days
in 1 day they together do 1/12 x=0.08333x

now b takes 25 days to complete half task
in 1 day b alone can do=0.5x/25=0.02x
so be can do work in 1/0.02 days=50days

now if a works alone he in one day can do=0.0833x-0.02x
=0.0633x
so a can complete work in 1/0.0633days=15.8 days

almost =16 days

let a do a amount of task x a day
so it takes x/a dats to do task completely
half task in x/2a days


let b do b amount of task x a day
so it takes x/b dats to do task completely
half task in x/2b days


x/2a+x/2b=25
2bx+2ax=,25ab
bx+ax=12.5ab
x=12.5ab/a+b

Answer 2

Answer:

Step-by-step explanation:

This problem is solve by trial method.I have attached the explanation.

In actual problem,  4 options  is given, out of 4 options one, A =30 days and B = 20 days is correct.