Question

A and B alone can complete work in 9 days and 18 days respectively. They worked together; however 3 days before the completion of the work A left. In how many days was the work completed?
1. 5
2. 6
3. 7
4. 8

Answer 1

Correct Answer - Option 4 : 8

Given:

A and B alone can complete work in 9 days and 18 days respectively.

Calculations:

Let the work be completed in x days.

According to the question,

A worked for (x –3) days, while B worked for x days.

so (x - 3)/9 + x/18 = 1

⇒ (2x - 6 + x)/18 = 1

⇒ 3x - 6 = 18

⇒ 3x = 24

⇒ x = 8

∴ the correct answer is 8 days.