Question

A car travels first 30 km with a uniform speed of 60 km h-1 and then next 30 km with a uniform speed of 40 km/h. Calculate (i) the total time of journey, (ii) the average speed of the car.

February 16, 2024

Answer

Distance travelled S₁ = 30 km

Speed v₁ = 60 km h^-1

Distance travelled S₂ = 30 km

Speed v₂ = 40 km h^-1

(i) As we know,

Time (t₁) = 30 / 60 = 0.5 h

Time (t₂) = 30 / 40 = 0.75 h

Total time t = t₁ + t₂ = 0.5 h + 0.75 h = 1.25 h

(ii) As we know,

Total distance S = S₁ + S₂

= 30 km + 30 km = 60 km

Avg speed = 60 /1.25 = 48 kmh^-1

Hence, the Average speed of the car = 48 kmh^-1

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