X , Y and Z can complete a work in 5 days, 15 days and 30 days, respectively. In how days can the work be completed if X is assisted by Y and Z together, on every second day?

Question

Question

This question was previously asked in

SSC CGL 2023 Tier-I Official Paper (Held On: 26 Jul 2023 Shift 3)

Answer 1

Given:

X , Y and Z can complete a work in 5 days, 15 days and 30 days, respectively.

Concept used:

Efficiency = (Total work / Total time taken)

Efficiency = work done in a single day

Calculation:

Let total work is 30 units ( Lcm of 5 . 15 and 30 )

The efficiency of X is

⇒ 30 / 5 = 6 unit

Again, the Efficiency of Y is,

⇒ 30 / 15 = 2 unit

Again, the Efficiency of Z is,

⇒ 30 / 30 = 1 unit

Total Efficiency,

⇒ 6 + 2 + 1= 9 unit

Efficiency of Y + Z = 3 units

Total work done in 1st, and 3rd day

⇒ 2 ×( 9+3) = 24 units

Y + Z together does in 2nd and 4 th day is, 3 × 2 = 6 units

The number of days required is 2 + 2 = 4 days

∴ The correct option is 2