​Raj is 60% more efficient than Sundar, and Sundar can finish a certain job in 16 days. How many days does Raj alone take to complete the same job? ​

Correct option is C

Given:

Raj is 60% more efficient than Sundar.

Sundar can finish the job in 16 days.

Formula Used: 

Efficiency = $$\frac{\text{Work Done}}{\text{Time Taken}}$$

Solution:

Sundar's efficiency:

Sundar can complete the job in 16 days, so his efficiency is $$\frac{1}{16}$$​​of the job per day.

Raj's efficiency:
Since Raj is 60% more efficient than Sundar, Raj's efficiency is 1.6 times that of Sundar.

Therefore, Raj's efficiency is:

Raj's efficiency = 1.6 × $$\frac{1}{16}$$ = $$\frac{1.6}{16}$$ = $$\frac{1}{10}$$​​

Since Raj completes $$\frac{1}{10}$$​ 110\frac{1}{10}

​of the job per day, he will take 10 days to complete the entire job.

Raj will take 10 days to complete the job alone.

Thus, option(C) is right.

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