R and S start walking each other at 10 AM at the speeds of 3 km/h and 4 km/h respectively. They were initially 17.5 km apart. At what time do they meet?	Choose the correct choice
A) 2 : 30 PM B) 11 : 30 AM C) 1 : 30 PM D) 12 : 30 PM E) None of these
Let after t hours they meet then,   3t + 4t = 17.5 ⇒ t = 25   ∴ Time = 10 am + 2.5 h = 12 : 30 am   Answer 12 : 30 PM
<result>D</result>
R and S start walking each other at 10 AM at the speeds of 3 km/h and 4 km/h respectively. They were initially 17.5 km apart. At what time do they meet?