<PRE><B>Question 1203959</B>
At noon, a cargo plane leaves Ling airport and heads towards Shangxu 500km away at 180km/h. 

At 1:00pm, a jet takes off from Ling airport and flies on the same course at 450km/h

Since the jet leaves one hour later , the cargo plane would have traveled 180 km

speed of cargo plane  180 km/h
speed of jet = 450 km/h

They are  flying in the same direction

Effective speed = 450 - 180 = 270 km/h

catch up time = catch up distance / catch up speed

time = 180/270  =2/3

Tje jet catches up after 2/3 hours = 40 minutes.

The jet will overtake the cargo plane at 1:40pm.


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