Um and difference of the speeds of two cars are 70km/hr & 30km/hr respectively. In a race, if the car with more speed finished 3 minutes earlier than the other. The racing distance was equal to?
Answers
Thus the speed of car A = 40 km/hr and speed of car B = 30 km/h
Explanation:
Points A and B are 70 km apart on a highway. A car starts from A and another car starts from B at the same time. If they travel in the same direction, they meet in 7 hours, but if they travel towards each other they meet in one hour. What are their speeds in km/hr?
Solution:
Speed = Distance / time
Speed of car at A = x+70 / 7
Speed of car at B = x / 7
Suppose they meet when A travels for y m, then B will have travelled 70−y m in the same time.
Speed of car at A = y / 1 = y
Speed of car at B = 70 - y / 1 = 70 - y
Equating the speeds of the cars in both the cases.
x + 70 = 7y
S = x - 7y = -70
Speed of car at B = x / 7 = 70 - y
S = x + 7y = 490
After equating we get:
Speed of car at A = x + 70 / 7 = 40 km/hr
Speed of car at B = x / 7 = 210 / 7 = 30 km/h
Thus the speed of car A = 40 km/hr and speed of car B = 30 km/h