While boarding an aeroplane, a passenger got hurt. The pilot showing promptness and concern, made arrangements to hospitalize the injured and so the plane started late by 30 minutes to reach the destination, 1500 km away in time, the pilot increased the speed by 100 km / hr. Find the original speed / hour of the plane.

Question

Philoid · Accepted Answer

Time = distance/speed

Given, while boarding an aeroplane, a passenger got hurt and the plane started late by 30 minutes to reach the destination, 1500 km away in time, the pilot increased the speed by 100km/hr.

Let the usual speed be ‘a’.

⇒ 2 × 1500 × (a + 100 –a) = a² + 100a

⇒ a² + 100a – 300000 = 0

⇒ a² + 600a – 500a – 300000 = 0

⇒ a(a + 600) – 500(a + 600) = 0

⇒ (a + 750)(a – 500) = 0

⇒ a = 500 km/hr