Question

Points A and B are 90 km apart from each other on a highway. A car starts from A and another from B at the same time. If they go in the same direction they meet in 9 hours and if they go in opposite directions they meet in 9/7 hours. Find their sppeds.

Answer 1

40, 30 kmph

Let the speeds of cars starting from A & B be a & b kmph respectively.

Travelling in same direction, let the cars meets at a distance 'd' from B, then

(90+d)/A = d/B = 9

=> A - B = 10 ——(i)

Travelling in opposite directions, 90/(A+B)=9/7

=> A+B=70 ——(ii)

Solving (i) & (ii), A=40, B=30