Answer:
a) 10:30 a.m.
b) 75 km/h
Explanation:
You want to know the leaving time and speed of a car from Woodlands to Muar if it left half an hour later and arrived half an hour earlier than a coach that traveled the 150 km distance at a speed of 50 km/h and arrived at 1 p.m..
Travel time
The travel time of the coach is found from the relation ...
time = distance/speed
time = (150 km)/(50 km/h) = (150/50) h = 3 h
Then the coach left Woodlands at ...
1 pm -3 h = 10 am
a) Leaving time
The car left half an hour later than the coach, so left at 10:30 a.m..
b) Speed
The car arrived at Muar at 12:30 p.m. so had a travel time of ...
12:30 -10:30 = 2 h
The speed over the 150 km distance is given by ...
speed = distance/time
speed = (150 km)/(2 h) = (150/2) km/h = 75 km/h
The average speed of the car was 75 km/h.
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Additional comment
The car passed the coach at 11:30 a.m., when both had covered half the distance.