X and Y start walking toward each other at 8 : 00 am at the speed of 3 km/h and 4 km/h. respectively. They were initially 17.5 km apart, at what time do they meet?
Correct Answer: 10 : 30 am
Explanation:
Let they meet after T h.
then, according to the question, 3T + 4T = 17.5
⇒ 7T = 17.5
∴ T = 17.5/7 = 2.5 h
So, they meet 2.5 h after 8 : 00 am.
It means they meet at 10 : 30 am.
