A is 40% more efficient than B. How much time will both, working together, take to finish the work, which B alone can finish in 36 days?

Question

Question

This question was previously asked in

SSC CGL 2022 Tier-I Official Paper (Held On : 12 Dec 2022 Shift 3)

Answer 1

Given:

A is 40% more efficient than B

B can complete the task in 36 days.

Concept used:

Total work = Efficiency of the worker × time taken by the worker

Calculation:

Let the efficiency of B be 10a

So, efficiency of A = 10a × 140%

⇒ 14a

So, total work = 10a × 36

⇒ 360a

Now,

If they both work then time = 360a/(14a + 10a)

⇒ 360a/24a

⇒ 360/24

⇒ 15

∴ The required answer is 15 days.

Shortcut Trick

A is 40% more efficient than B, then the efficiency of A : B = 140 : 100 = 7 : 5

B alone can finish in 36 days, then total work = (5 × 36) = 180 unit

If A & B both working together, time taken = 180/(7 + 5) = 180/12 = 15 days