Multiple choice

A train going at 90 km/hr takes 35 minutes to travel a certain distance. By how much should it increase its speed (in km/hr) to travel the same distance in 21 minutes?

  1. 60

  2. 150

  3. 120

  4. 90
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Distance = Speed × Time = 90 × (35/60) = 52.5 km. To cover 52.5 km in 21 minutes, needed speed = 52.5 / (21/60) = 52.5 × 60/21 = 150 km/hr. Increase needed = 150 - 90 = 60 km/hr. Use consistent units (convert minutes to hours) and relate distance = speed × time.

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