Pamela started jogging from the farm to the park at a speed of 95 m/min at 6 a.m. Her cousin started jogging from the farm later. They were beside each other at 6.40 a.m. and her cousin reached the park at 7 a.m. while Pamela was still 1900 m away. If both of them travelled at a constant speed throughout the journey, what time did her cousin leave the farm?
1 h = 60 min

From 6 a.m. to 7 a.m. = 1 h
From 6.40 a.m. to 7 a.m. = 20 min

Distance between the farm and the park
= 60 x 95 + 1900
= 5700 + 1900
= 7600 m

Distance that Pamela's cousin had to cover to catch up with Pamela
= 40 x 95
= 3800 m

Distance that Pamela's cousin travelled to the park after catching up with Pamela
= 7600 - 3800
= 3800 m

Since Pamela's cousin jogged 3800 m in 40 min,
Pamela's cousin average speed
= 3800 ÷ 20
= 190 m/min

Duration that Pamela's cousin took to jog to the park
= 7600 ÷ 190
= 40 min

Time that Pamela's cousin left the farm:
40 min before 7 a.m. = 6.20 a.m.

Answer(s): 6.20 a.m.