Question

Ravi, Rohan and Rajesh alone can complete a work in 10, 12 and 15 days respectively. In how many days can the work be completed, if all three work together?

• A. 4 days
• B. 5 days
• C. 3 days
• D. 8 days

Answer 1

Answer:

A. 4 days

Ravi can complete a work in = 10 days

∴ In 1 day Ravi can do = $\frac{1}{10}$

Rohan alone can complete a work in = 12 days

∴ In 1 day Rohan can do = $\frac{1}{12}$

Rajesh alone can complete a work in = 15 days

∴ In 1 day Rajesh can do = $\frac{1}{15}$

∴ In 1 day they together can do = $\frac{1}{10} + \frac{1}{12} + \frac{1}{15}$ = $\frac{(6 + 5 + 4)}{60} =\frac{1}{4}$

∴ They together can complete the work in = 4 days