Multiple choice

A man covered a certain distance at some speed. If he increases his speed by 4km/h then he would have reached 9/2 min early then usual time. If he decreased his speed by 6 km/h then he had reached 8 min late. Find the original distance? एक व्यक्ति कुछ दूरी किसी समय में पूरी करता है। यदि उसकी चाल 4 किमी/ घंटे से बड़ जाये तो वह नियत समय से 9/2 मिनट पहले ही पहुंच जायेगा। यही वह अपनी चाल 6 किमी/ घंटे की चाल से घटा ले तो वह 8 मिनट की देरी से पहुंचेगा। तो वह दूरी ज्ञात करो?

  1. 60 km

  2. 54 km

  3. 64 km

  4. 72 km

  5. None of these इनमे से कोई नहीं

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

Let original speed be v km/h and distance be d km. When speed increases by 4 km/h, time saved is 9/2 min. When speed decreases by 6 km/h, time lost is 8 min. Using d/(v+4) = d/v - 9/120 and d/(v-6) = d/v + 8/60, solving gives d = 72 km. Option D is correct.