Question

a car left the city travelling uniformely at a speed of 80km/h it was followed 1.5 hour later by a motorcycle whose speed was 100 km/h. How much time did the motor cycle take to catch the car ? Where dose it takes place​

Answer 1

after 6 hours at 600 km

Answer 2

Answer:

7.5

Explanation:

The correct answer is: The car travelled for 7.5 hours

The diagram below shows the motion of the car and the bike.

Let the time the bike travels till it catches up with the car be T hours.

Then from the diagram it is clear that:

Distance travelled by the bike = 100 km/h  \times×  T hours = 100T km

Distance travelled by the car = (80 km/h \times× 1.5 hours) + (80 km/h \times× T hours) = (120 + 80T) km

As both car and bike travel the same distance:    100T  = (120 +80T)   \Rightarrow⇒  20T = 120   \Rightarrow⇒ T = 6

So the bike was travelling for 6 hours.   But the question is how long was the car travelling.

The car started 1.5 hours earlier.  So the car was travelling for 6 + 1.5 = 7.5 hours.