Question

P alone can complete work in 18 days and Q alone can complete the work in 24 days. P and Q work for 8 days together then Q left the work remaining work will be completed by P in -
1. 3 days
2. 12 days
3. 4 days
4. 6 days

Answer 1

Correct Answer - Option 3 : 4 days

Given:

P can complete a work in 18 days

Q can complete a work in 24 days

Calculation:

P's 1 days work = 1/18

Q's 1 days work = 1/24

(P + Q)'s 1 days work = 1/18 + 1/24 = 7/72

⇒ (P + Q)'s 8 days work = 8 × 7/72 = 7/9

Remaining work after 8 days = 1 - 7/9 = 2/9

Remaining work will be completed by P in = 2/9 × 18 = 4 days

∴ Remaining work will be completed by P in 4 days