IIMB 2001 (QA) PYQs

Two trains, Patna Express and Delhi Express, set off at the same time from Patna and Delhi, respectively, heading towards each other. After crossing each other, the Patna Express takes $12$ hours to reach Delhi, while the Delhi Express takes $3$ hours to reach Patna. If the Patna Express travels at a speed of $48$ km/hr, what is the speed of the Delhi Express?

A car travels the first $160$ km at a speed of $64$ km/hr and the next $160$ km at a speed of $80$ km/hr . What is the average speed for the first $320$ km of the tour ?

Ash Ketchum on a journey completed his travels using two modes of transport: walking and riding a bicycle. Ash walked a total of 90 km and rode the bicycle for 10 km. The time he spent riding the bicycle was four hours less than the time he spent walking. If the times spent on each mode of transport were swapped, the distances covered by walking and riding would be equal. How long did Ash spend riding the bicycle?