Practicing Success
Places A and B are 144 km apart. Two cars start simultaneously, one from A and the other from B. If they move in the same direction, they meet after 12 hours, but if they move towards each other they meet after $\frac{9}{8}$ hours. The speed (in km/h) of the car moving at a faster speed, is: |
70 72 60 64 |
70 |
We know , Speed = \(\frac{Distance}{Time}\) Let speed of 1st car = a km/h & speed of 2nd car = b km/h Relative speed when moves in same direction = (a - b) km/h Relative speed when moves in opposite direction = (a + b) km/h According to question , ( a - b ) = \(\frac{144}{12}\) = 12 km/h & ( a + b ) = \(\frac{144 × 8}{9}\) = 128 km/h 2a = 12 + 128 = 140 a = 70 km/h So , speed of 1st car = 70 km/h |