A car starts from A for B travelling 20 km an hour.1 1/2 hours later another car starts from A and travelling at the rate of 30 km an hour reaches B 2 1/2 hours before the first car. Find the distance from A to B.
Choose the correct choice from the following choices
A) 280 km  B) 260km  C) 240km  D) 340km  E) None of these
Let the distance between A and B be x   The second car stars 1.5 hour later and reaches 2.5 hour early then first car   so the time difference is 4 hours.   Thus, x/20 - x/ 30 = 4   or, x = 240   ANSWER:240km
<result>C</result>
A car starts from A for B travelling 20 km an hour.1 1/2 hours later another car starts from A and travelling at the rate of 30 km an hour reaches B 2 1/2 hours before the first car. Find the distance from A to B.