Question

Running at 3/4^th of his usual speed, an athlete takes 5minutes more to complete the race.
What is the time he usually takes to run the same distance?

• A. 15 minutes
• B. 17 minutes
• C. 20 minutes
• D. 25 minutes

Answer 1

The correct option is A 15 minutes

Let us assume the usual speed of athlete be v units/minute, and usual time to be t minutes.
As, distance = speed × time
speed₁ × time₁ = speed₂ × time₂
Putting values we get,
So, v × t = (3v/4) × (t+5)
Or 4t = 3t + 15
Or t = 15 minutes
Hence, option (a) is correct.

माना कि समान्य गति (चाल) V इकाई/मिनट और समान्य समय t मिनट है।
चूंकि, दूरी = चाल₁ × समय₁ = चाल₂ × समय₂)
इसलिए, V × t = (3v/4) × (t + 5)
या 4t = 3t + 15
या t = 15 मिनट