Multiple choice

Sharad covers two-thirds of a certain distance at 4 km/hr and the remaining at 5 km/hr. If he takes 42 minutes in all, then the distance is

  1. 2.5 km

  2. 4.6 km

  3. 4 km

  4. 3 km
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let total distance be D. (2/3)D/4 + (1/3)D/5 = 42/60. D/6 + D/15 = 0.7. (5D + 2D)/30 = 0.7. 7D/30 = 0.7. D = 3 km.

AI explanation

Let the total distance be x kilometers, meaning he covers (2/3)x at 4 km/hr and (1/3)x at 5 km/hr. Using the time formula, the equation is (2x/12) + (x/15) equals 42/60 hours. Finding a common denominator of 60 gives (10x + 4x) / 60 equals 0.7. Solving 14x equals 42 yields x equals 3 km.

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