Question

A can complete 3/4th of the task in 15 days and his son B can complete the same task in 40 days . if they work together in how many days the task is completed ?

Answer 1

Answer:

Since the same amount of work is done by both A and B.let us consider it as A =15 days and B=40days then A+B= 40+15=55days.

Answer 2

Answer:

13.33 days

Step-by-step explanation:

In the question,

Time taken by A to complete 3/4 of a task = 15 days

Time taken by his son to complete same task = 40 days

So,

Time taken by A to complete the full task is,

$15\times \frac{4}{3}=20$ days

Now,

Let us say the time taken by them to complete the task on working together is = x days

So,

Work done by father in 1 day + Work done by son in 1 day = Work done in 1 day

So,

$\frac{1}{20}+\frac{1}{40}=\frac{1}{x}\\So,\\\frac{3}{40}=\frac{1}{x} \\x=\frac{40}{3}$

Therefore, the time taken by them to complete the task is $\frac{40}{3}$ days.

Therefore, it takes 13.33 days to complete the task together.