Piyush and Kesari start at the same time to travel from place P to place Q, which are 100 km apart. Piyush travels 5 km/hr slower than Kesari. Kesari reaches Q, turns back at once and meets Piyush 20 km from Q. What is Kesari’s speed (in km/hr)?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 15
Until they meet, both travel for the same time, so the distances they cover are in the ratio of their speeds.
Kesari covers \(100+20=120\) km (to Q and 20 km back)
Piyush covers \(100-20=80\) km
Let Kesari’s speed be \(k\) km/hr; Piyush’s speed is \(k-5\)
Equal times: \(\displaystyle \frac{120}{k}=\frac{80}{k-5}\)
\(120k-600=80k\), so \(40k=600\) and \(k=15\) km/hr