Multiple choice

A train covers a certain distance in 50 minutes, if it runs at a speed of 48 kmph on an average. The speed in kmph at which the train must run to reduce the time of journey to 40 minutes will be एक रेलगाड़ी एक निश्चित दूरी 50 मिनटों में तय कर लेती है। यदि वह रेलगाड़ी 48 किमी प्रति घंटा की औसत गति से चल रही हो, तो उसे वह दूरी 40 मिनटो में पूरी करने के लिए, किस गति (किमी/घं) से चलना होगा?

  1. 64

  2. 60

  3. 54

  4. 56.5

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Distance = Speed × Time = 48 kmph × (50/60) hours = 40 km. To cover same 40 km in 40 minutes (40/60 = 2/3 hours), required speed = Distance/Time = 40 ÷ (2/3) = 40 × 3/2 = 60 kmph. Speed and time are inversely proportional for constant distance. Option B is correct.