Question 93

Srinivas can do a job in 15 days and Rameshcando the same job in 9 days. With the help of Ravi, they did the job in 3 days. In how many days can Ravi alone do the same job?

Solution

Let say, Ravi do the job in x days .

So, $$\frac{1}{x}+\frac{1}{15}+\frac{1}{9}=\frac{1}{3}.$$

or,$$\frac{1}{x}=\frac{1}{3}-\frac{1}{15}-\frac{1}{9}.$$

or,$$\frac{1}{x}=\frac{15-3-5}{45}.$$

or,$$x=\frac{45}{7}=6\frac{3}{7}.$$

D is correct choice.

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