Question

Rahul does 1/3 of a work in 9 days then Ronit joined him and they together completed the remaining work in 6 days. Ronit alone can finish the whole work in:
1. 25/2
2. 27/2
3. 29/2
4. 27

Answer 1

Correct Answer - Option 2 : 27/2

Given:

Work done by Rahul in 9 days = 1/3 part of the whole work 

Work done by (Rahul + Ronit) in 6 days = 2/3 part of the whole work 

Calculation:

Let the number of days required to complete 1 unit of work by Ronit be x days and 

Let the total work be 1 unit

Work done by Rahul in 9 days is 1/3

Number of days required to complete 1 unit of work by Rahul = 3 × 9 = 27 days

Work done by Ronit and Rahul in 6 days is 2/3

Number of days required to complete 1 unit of work by Rahul and Ronit = 9 days

Now, according to the question,

(1/x) + (1/27) = 1/9

⇒ (27 + x)/27x = 1/9

⇒ 27 + x = 3x

⇒ x = 27/2 days

∴ Ronit alone can finish the whole work in 27/2 days.