Irene started jogging from the hospital to the park at a speed of 114 m/min at 6 a.m. Her cousin started jogging from the hospital later. They were beside each other at 6.35 a.m. and her cousin reached the park at 7 a.m. while Irene was still 1900 m away. If both of them travelled at a constant speed throughout the journey, what time did her cousin leave the hospital?
1 h = 60 min

From 6 a.m. to 7 a.m. = 1 h
From 6.35 a.m. to 7 a.m. = 25 min

Distance between the hospital and the park
= 60 x 114 + 1900
= 6840 + 1900
= 8740 m

Distance that Irene's cousin had to cover to catch up with Irene
= 35 x 114
= 3990 m

Distance that Irene's cousin travelled to the park after catching up with Irene
= 8740 - 3990
= 4750 m

Since Irene's cousin jogged 4750 m in 35 min,
Irene's cousin average speed
= 4750 ÷ 25
= 190 m/min

Duration that Irene's cousin took to jog to the park
= 8740 ÷ 190
= 46 min

Time that Irene's cousin left the hospital:
46 min before 7 a.m. = 6.14 a.m.

Answer(s): 6.14 a.m.