Rahul and Shyam, working together, can do a piece of work in 5 hours; Rahul alone can do the same work in 15 hours. How much time will Shyam alone take to do that work?
Answer & explanation
Correct answer: option 3
Rahul + Shyam, = 5 hours,
Shyam = 15 hours,
⇒Rahul + Shyam = 3 (Efficiency)
⇒ 1 + Shyam = 3,
⇒ Shyam = 2,
⇒ Therefore, Time required by Shyam to complete the work alone = \(\frac{15}{2}\) = 7.5 hours. ..(\(\frac{Work}{Efficiency}\) = Time)