Ram and Shyam together can complete a work in 12 days. Shyam alone can complete the work in 15 days. Shyam alone worked for 5 days. After that, how long will Ram alone take to complete the work?

Correct option is D

Given:

Ram and Shyam together can do work in 12 days

Shyam alone can do the work in 15 days

Formula Used:

Let total work be 1.

Then work done 1 day = $$\frac{1}{Total\ time\ to\ work}$$​​

Solution:

Ram and Shyam’s one day’s work = $$\frac{1}{12}$$​​

Shyam’s one day’s work = $$\frac{1}{15}$$​​

Ram’s one day work = $$\frac{1}{12} - \frac{1}{15} = \frac{5-4}{60} = \frac{1}{60}$$​​

Shyam’s five day’s work = $$5 \times \frac{1}{15} = \frac{1}{3}$$​​

Total work left = $$1 - \frac{1}{3} = \frac{2}{3}$$​​

Time taken by Ram to finish the work = $$\frac{Work\ left}{Ram’s \ one \ day’s \ work} = \frac{\frac{2}{3}}{\frac{1}{60}} = 40 \ days$$​