Multiple choice

Payal can cover a certain distance in $1hr24 mins$ by covering two-thirds of the distance at $4 km/hr$ and the rest at $5 km/hr$. Find the total distance.

  1. $2$ km
  2. $4$ km
  3. $8$ km
  4. $6$ km
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let total distance be D. Time = (2/3)D/4 + (1/3)D/5 = 1.4 hours (84 minutes). D/6 + D/15 = 1.4. Multiplying by 30 gives 5D + 2D = 42, so 7D = 42, D = 6 km.

AI explanation

The total time of 1 hour 24 minutes converts to 1 + 24/60 hours, which is 1.4 hours. Let the total distance be d km; the time taken for the first part is (2d/3) / 4 = d/6 hours, and the time for the second part is (d/3) / 5 = d/15 hours. The equation for the total time is d/6 + d/15 = 1.4, and finding a common denominator gives 5d/30 + 2d/30 = 1.4, simplifying to 7d/30 = 1.4. Solving for d gives 7d = 42, so d = 6 km. The result is 6 km.

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