Question

A can do a certain job in 25 days which B alone can do in 20 days. A started the work and was joined
by B after 10 days. The work lasted for how many days? ​

Answer 1

Step-by-step explanation:

Work done by A in l0 days = (1/25) *10 = 2/5

Remaining work = 1 - (2/5) = 3/5

(A+B)s 1 days work = (1/25) + (1/20) = 9/100

9/100 work is done by them in 1 day.

hence 3/5 work will be done by them in (3/5)*(100/9)

= 20/3days.

Total time taken = (10 + 20/3) = 16*(2/3) days

Answer 2

Step-by-step explanation:

Work done by A in l0 days = (1/25) *10 = 2/5

Remaining work = 1 - (2/5) = 3/5

(A+B)s 1 days work = (1/25) + (1/20) = 9/100

9/100 work is done by them in 1 day.

hence 3/5 work will be done by them in (3/5)*(100/9)

= 20/3days.

Total time taken = (10 + 20/3) = 16*(2/3) days