Marion started jogging from the temple to the park at a speed of 105 m/min at 9 a.m. Her cousin started jogging from the temple later. They were beside each other at 9.36 a.m. and her cousin reached the park at 10 a.m. while Marion was still 1800 m away. If both of them travelled at a constant speed throughout the journey, what time did her cousin leave the temple?
1 h = 60 min

From 9 a.m. to 10 a.m. = 1 h
From 9.36 a.m. to 10 a.m. = 24 min

Distance between the temple and the park
= 60 x 105 + 1800
= 6300 + 1800
= 8100 m

Distance that Marion's cousin had to cover to catch up with Marion
= 36 x 105
= 3780 m

Distance that Marion's cousin travelled to the park after catching up with Marion
= 8100 - 3780
= 4320 m

Since Marion's cousin jogged 4320 m in 36 min,
Marion's cousin average speed
= 4320 ÷ 24
= 180 m/min

Duration that Marion's cousin took to jog to the park
= 8100 ÷ 180
= 45 min

Time that Marion's cousin left the temple:
45 min before 10 a.m. = 9.15 a.m.

Answer(s): 9.15 a.m.