PSLE
Ginny and Emily 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. Ginny jogged past Emily after 10 km. Both of them did not change their speeds throughout. Ginny took 30 min to complete one round. What was Emily's jogging speed in m/min?
Distance that Emily jogged when they passed each other
= 15 - 10
= 5 km

Time that Ginny took to jog 15 km = 30 min

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

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

When Ginny took 20 min to jog 10 km, Emily took the same time to jog 5 km.

1 km = 1000 m
5 km = 5000 m

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

Answer(s): 250 m/min