Multiple choice

A man travelled by car from cities X to Y. It took him 80 minutes to complete the journey. For first 20 minutes, his average speed was 36 km/hr, for next 30 minutes, it was 48 km/hr and for the remaining 30 minutes, it was P km/hr. If the total distance travelled by him was 92 km, then find the average speed of the car in last 30 minutes.

  1. 96 km/hr

  2. 108 km/hr

  3. 112 km/hr

  4. 116 km/hr

  5. 120 km/hr
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Total distance = 92 km. Dist1 = 20/60 * 36 = 12 km. Dist2 = 30/60 * 48 = 24 km. Dist3 = 92 - 12 - 24 = 56 km. Time3 = 30/60 = 0.5 hours. Speed3 = 56 / 0.5 = 112 km/hr.

AI explanation

Using the Distance formula, the distance covered in the first 20 minutes at 36 km/hr is 36 multiplied by (20 divided by 60), which equals 12 km. The distance covered in the next 30 minutes at 48 km/hr is 48 multiplied by (30 divided by 60), which equals 24 km. Subtracting these from the total distance gives the remaining distance: 92 minus 12 minus 24 equals 56 km. Using the Speed formula where Speed equals Distance divided by Time, the speed for the last 30 minutes is 56 divided by 0.5, which equals 112 km/hr. The average speed of the car in the last 30 minutes is 112 km/hr.

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