A bus travelling at 72 km/h completes a journey in 15 hours. At what speed will it have to cover the same distance in 12 hours?

Given:

Initial speed (S₁) = 72 km/h

Time taken (T₁) = 15 hours

Time required (T₂) = 12 hours

Formula used:

S₂ = (S₁ × T₁) / T₂

Where,

S₂ = New speed, S₁ = Initial speed

T₁ = Initial time, T₂ = New time

Calculation:

S₂ = (72 × 15) / 12

⇒ S₂ = 1080 / 12

⇒ S₂ = 90 km/h

∴ The correct answer is option (2).