Question

(1) Acar moves with a speed of 40 km/h for 15 min and then with a speed of 60 km/h for
the next 15 min. What is the total distance covered by the car ?
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Answer 1

This is the required answer.

Answer 2

The total distance travelled by the car is 25 km.

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• According to the first condition,

Speed of the car = 40 km/h

Time for which the car travels = 15 min

• Now, 15 min has to converted into hours to make the units of speed and time same.

∴  15 min = 15 / 60 h

Or, 15 min = 1 / 4 h

• Therefore, distance travelled by the car in first 15 minutes (d₁) = speed × time = (40 km/h) × (1/4 h)

Or, distance travelled (d₁) = 10 km

• According to the second condition,

Speed of the car = 60 km / h

Time for which the car travels = 15 min = 1 / 4 h

• Therefore, distance travelled by the car in the next 15 minutes (d₂) = speed × time = (60 km/h) × ( 1/4 h)

Or, distance travelled (d₂) = 15 km

• The total distance travelled by the car in 30 minutes = d₁ + d₂

=> Total distance travelled = 10 km + 15 km

Or, total distance travelled = 25 km