Mr Tan took 4 hours to travel from Town A to Town B. Mr Lim took 8 hours to travel in the opposite direction from Town B to Town A using the same route. They both started at 11am. What time did they pass each other? Answer ... pm

1. Find their combined fraction of the route travelled in 1 hour

Let the distance from Town A to Town B be $1$ whole route.

Mr Tan's rate $= \dfrac{1}{4}$ route per hour.

Mr Lim's rate $= \dfrac{1}{8}$ route per hour.

Combined rate towards each other
$=\dfrac{1}{4}+\dfrac{1}{8}=\dfrac{3}{8}$
route per hour.

2. Find the time after 11 am when they meet and convert to clock time

Time taken to meet
$=1\div \dfrac{3}{8}=\dfrac{8}{3}\text{ h}$
$=2\text{ h }40\text{ min}$

They started at 11 am, so they passed each other at
$11\text{ am}+2\text{ h }40\text{ min}=1.40\text{ pm}.$