SOLUTION: A bus left mombasa and travelled towards nairobi at an average speed of 60km/hr. After two and a half hours, a car left mombasa and travelled along the same road at an average spee

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Question 1101384: A bus left mombasa and travelled towards nairobi at an average speed of 60km/hr. After two and a half hours, a car left mombasa and travelled along the same road at an average speed of 100km/hr. if the distance between mombasa and nairobi is 500km. determine
a) i)the distance of the bus from nairobi when the car took off .
ii) the distance the car travelled to catch up with the bus.
b) immediately the car caught up with the bus, the car stopped for 25 minutes. find the new average speed at which the car travelled in order to reach Nairobi at the same time as the bus.

Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
a) i) After travelling for 2.5hours ,
the bus had covered a distance of
%28%2260+km+%2F+hr+.%22%29%282.5hours%29=150km ,
so the distance of the bus from Nairobi when the car took off was highlight%28150km%29 .

ii) The car was moving at a speed
%22100+km+%2F+hr+.%22-%2260+km+%2F+hr+.%22=%2240+km+%2F+hr+.%22 faster than the bus,
so it was shortening the distance between them at that rate.
It would have taken 150km%2F%2240+km+%2F+hr+.%22=3.75+hours to catch up with the bus.
During that time, the car would travel
%28%22100+km+%2F+hr+.%22%29%283.75hours%29=375km ,
so the distance the car travelled to catch up with the bus was
highlight%28375km%29 .

b) At the time the car caught up with the bus,
they both were 500km-375km=125km away from Nairobi.
It would take the bus another 125km%2F%2260+km+%2F+hr+.%22=125%2F60hours to get to Nairobi.
That is 125minutes or 2%265%2F60hours or 2 hours and 5 minutes.
As the car stopped for 25 minutes, to get to Nairobi at the same time as the bus,
it would have to travel the remaining 125 km in
125 minutes - 25 minutes = 100 minutes.
That is 100%2F60hours=5%2F3hours .
For that to happen, its average speed, in km/hr. would have to be
125%2F%225+%2F+3%22=125%283%2F5%29=75 .
The new average speed at which the car travelled in order to reach Nairobi at the same time as the bus was highlight%28%2275+km+%2F+hr+.%22%29 .