PSLE
Mara and Kitty started jogging from the same point of the 12 km track round a lake. They started at the same time but in opposite directions. Mara jogged past Kitty after 10 km. Both of them did not change their speeds throughout. Mara took 15 min to complete one round. What was Kitty's jogging speed in m/min?
Distance that Kitty jogged when they passed each other
= 12 - 10
= 2 km

Time that Mara took to jog 12 km = 15 min

Time that Mara took to jog 1 km
= 15 ÷ 12
= 1.25 min

Time that Mara took to jog 10 km
= 10 x 1.25
= 12.5 min

When Mara took 12.5 min to jog 10 km, Kitty took the same time to jog 2 km.

1 km = 1000 m
2 km = 2000 m

Kitty's jogging speed
= 2000 ÷ 12.5
= 160 m/min

Answer(s): 160 m/min