Question

A flight left 30 minutes later than the scheduled time and in order to reach its destination 1500 km away in time it has to increase its speed by 250 km/hr from its usual speed. Find its usual speed.

Answer 1

Let the usual speed of the flight be km/h 

∴ 1500/x − 1500/(x+250) = 30/60 

⟹ x² + 250x − 750000 = 0 

(x − 750)(x + 1000) = 0 

∴ x = 750 (Rejecting negative value) 

Hence the usual speed of the flight = 750 km/h