Question

A car covers a certain distance in two hours with the speed of 60km/hr and it covers further certain distance in three hours with the speed of 25m/sec calculate the average speed of the car

Answer 1

Let's simplify the second equation first.
it says
1 sec = 25m then
60 sec = 25 X 60 m
1 min= 25 X 60 m
60 min = 25 X 60 X 60 m
1 hr = 25 X 60 X 60 m
3 hr = 25 X 60 X 60 X 3 m
= 270000 m
= 270 km in 3 hr.
The first equation says
1 hr = 60 km
2 hr= 60 X 2 = 120 km

So
average speed = total distance/ total time
= 270 km + 120 km / 3 hr + 2hr
= 390km / 5 hr = 98km/hr