PSLE
Penny and Opal started jogging from the same point of the 15 km track round a housing estate. They started at the same time but in opposite directions. Penny jogged past Opal after 10 km. Both of them did not change their speeds throughout. Penny took 30 min to complete one round. What was Opal's jogging speed in m/min?
Distance that Opal jogged when they passed each other
= 15 - 10
= 5 km

Time that Penny took to jog 15 km = 30 min

Time that Penny took to jog 1 km
= 30 ÷ 15
= 2 min

Time that Penny took to jog 10 km
= 10 x 2
= 20 min

When Penny took 20 min to jog 10 km, Opal took the same time to jog 5 km.

1 km = 1000 m
5 km = 5000 m

Opal's jogging speed
= 5000 ÷ 20
= 250 m/min

Answer(s): 250 m/min