Hello, Chr2010!

A jet flew from Tokyo to Bangkok, a distance of 4800km.

On the return trip, the speed was decreased by 200 km/hr.

If the difference in the times of the flight was 2 hours,

what was the jet's speed from Bangkok to Tokyo?

The jet flew 4800 km from Bangkok to Tokyo at km/hr.

. . This took hours.

The jet flew 4800 km from Tokyo to Bangkok at km/hr.

. . This took hours.

The difference in time was 2 hours: .

Multiply by

This equation simplifies to: .

. . whoch factors: .

. . and has roots: .

The jet's speed from Bangkok to Tokyo was 600 km/hr.