A car  from point A towards point B, travelling at the speed of 20 km/h. $1\frac{1}{2}$ hours later, another car starts from point A and travelling at the speed of 30 km/h and reaches $2\frac{1}{2}$ hours before the first car. Find the distance between A and B.

240 km

Let the total distance = A km,

In 1.5 hr Distance traveled by 1st car with 20 km/h speed =  30 km

Remaining distance =  (A - 30) km

According to the question,

\(\frac{(A-30)}{20}\) - \(\frac{(A)}{30}\) = \(\frac{(5)}{2}\) 

on solving ,

A - 90 = 150

A = 240 km

So total distance = 240 km