Question

A takes 50% more time than B to complete a task. If both work together, they take 18 days to complete the task. Accordingly, if B works alone then in how many days will he complete the work?
1. 30 days
2. 35 days
3. 40 days
4. 45 days

Answer 1

Correct Answer - Option 1 : 30 days

Given:

Time taken to complete a piece of work by B = x 

Time taken to complete same work  by A = x + 50%

Formula used:

Efficiency = Work/Time

Calculation:

Let us consider the number of days B requires to complete the work = x days 

So, number of days A requires to complete the work = x + (50/100)x = 1.5x

We can calculate, work done by A in 1 day = 1/1.5x = 2/3x

And work done by B in 1 day = 1/x

We know that the number of days A and B together requires to do work = 18 days 

So, work done by both A and B in 1 day = 1/18

⇒ 2/3x + 1/x = 1/18

⇒ 5/3x = 1/18

⇒ x = (5× 18)/3

⇒ x = 30

∴ B requires 30 days to complete the work.