Question

On a long stretch of east-west road, A and B are two points such that B is 350 km west of A. One car starts from A and another from B at the same time. If they move towards each other, then they meet after 1 hour. If they both move towards east, then they meet in 7 hrs. The difference between their speeds, in km per hour, is

Accepted Answer

50. Let the speed of the car starting from B be $v_B$ and the car starting from A be $v_A$. Since both move towards east and meet, car B catches up to car A, so relative speed in same direction $= v_B - v_A$. Distance $= 350	ext{ km}$. When moving towards east, they meet in 7 hours: $$v_B - v_A = \frac{350}{7} = 50	ext{ km/h}$$ Hence, the difference between their speeds is $50	ext{ km/h}$.

Difference between speeds of two cars

Explanation

Practise this under exam conditions