The distance between two places A and B is 140 km. Two cars x and y start simultaneously from A and B respectively. If they move in the same direction, they meet after 7 hours. If they move towards each other, they meet after one hour. What is the speed (in km/h) of car y if its speed is more than that of car x?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 80.
Let the speed of Car x and y be 'a' and 'b' km/hr.
If they move in the same direction, they meet after 7 hours
140/(b - a) = 7
(b - a) = 20.............(1)
If they move towards each other, they meet after one hour,
140/(a + b) = 1
a + b = 140............(2).
on adding eq (1) and (2) we get,
2b = 160
b = 80 km/hr.