Question

A can do a task in 15 days, B works 50% faster than A. In how many days can B alone finish ?
1. 10
2. 12
3. 8
4. 15

Answer 1

Correct Answer - Option 1 : 10

Given:

Time taken by A to do a task alone = 15 days

B works 50% faster than A

Formula Used:

Work Done = Time × Efficiency

Calculation:

Let the efficiency of A be x

So, the efficiency of B = [(100 + 50)/100] × x = 1.5x

From the basic relation between work done and efficiency, 

⇒ Time ∝ (1/Efficiency)

So, we get the respective ratios of time and efficiency as:

⇒ (Time taken by A alone)/(Time taken by B alone) = (Efficiency of B)/(Efficiency of A)

⇒ (15 days)/(Time taken by B alone) = 1.5x/x

⇒ Time taken by B alone= (15 days)/(1.5) = 10 days

∴ The time taken by B alone is 10 days