Ravi completes a work in 10 days. He and Ajay complete the same work in 4 days. What will be the time taken by Ajay to complete the same work?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 6.67 days
A person who finishes a work in \(n\) days does \(\frac{1}{n}\) of it in one day, and the day’s work of two people working together is the sum of their separate day’s work. So Ajay’s day’s work is the joint day’s work minus Ravi’s.
Ravi’s one day’s work \(\displaystyle =\frac{1}{10}\); Ravi and Ajay together \(\displaystyle =\frac{1}{4}\)
Ajay’s one day’s work \(\displaystyle =\frac{1}{4}-\frac{1}{10}=\frac{5-2}{20}=\frac{3}{20}\)
Ajay alone takes \(\displaystyle \frac{20}{3}=6\frac{2}{3}\) days, that is about 6.67 days