PSLE
Riley and Penny started jogging from the same point of the 10 km track round a nature reserve. They started at the same time but in opposite directions. Riley jogged past Penny after 4 km. Both of them did not change their speeds throughout. Riley took 40 min to complete one round. What was Penny's jogging speed in m/min?
Distance that Penny jogged when they passed each other
= 10 - 4
= 6 km

Time that Riley took to jog 10 km = 40 min

Time that Riley took to jog 1 km
= 40 ÷ 10
= 4 min

Time that Riley took to jog 4 km
= 4 x 4
= 16 min

When Riley took 16 min to jog 4 km, Penny took the same time to jog 6 km.

1 km = 1000 m
6 km = 6000 m

Penny's jogging speed
= 6000 ÷ 16
= 375 m/min

Answer(s): 375 m/min