PSLE
Charlie and Olivia started jogging at the same time from point W to point Y along the route shown. Charlie jogged 20 m/min faster than Olivia. When Charlie reached point Y, he turned around at once to jog towards point W. He met Olivia at point X. They did not change their speeds throughout. What was Olivia's jogging speed in m/min?
Extra distance covered by Charlie
= 2 x 600
= 1200 m

Charlie covered the extra 1200 m because he jogged 20 m/min faster than Olivia.

Time taken by Charlie to reach 5460-m mark
= 1200 ÷ 20
= 60 min

The time taken by Charlie and Olivia to jog until they met each other was the same.

Olivia's speed
= 5460 ÷ 60
= 91 m/min

Answer(s): 91 m/min