A bus travelling at 87 km/h completes a journey in 15 hours. At what speed will it have to cover the same distance in 9 hours?

Given:

Speed of bus (S₁) = 87 km/h

Time taken (T₁) = 15 hours

New time required (T₂) = 9 hours

Formula used:

Distance (D) = Speed × Time

For constant distance: S₁ × T₁ = S₂ × T₂

Calculation:

Distance = 87 × 15

⇒ D = 1305 km

New speed required (S₂):

⇒ S₂ = D ÷ T₂

⇒ S₂ = 1305 ÷ 9

⇒ S₂ = 145 km/h

∴ The correct answer is option (2).