Barbara started jogging from the florist to the garden at a speed of 105 m/min at 7 a.m. Her cousin started jogging from the florist later. They were beside each other at 7.41 a.m. and her cousin reached the garden at 8 a.m. while Barbara was still 1900 m away. If both of them travelled at a constant speed throughout the journey, what time did her cousin leave the florist?
1 h = 60 min

From 7 a.m. to 8 a.m. = 1 h
From 7.41 a.m. to 8 a.m. = 19 min

Distance between the florist and the garden
= 60 x 105 + 1900
= 6300 + 1900
= 8200 m

Distance that Barbara's cousin had to cover to catch up with Barbara
= 41 x 105
= 4305 m

Distance that Barbara's cousin travelled to the garden after catching up with Barbara
= 8200 - 4305
= 3895 m

Since Barbara's cousin jogged 3895 m in 41 min,
Barbara's cousin average speed
= 3895 ÷ 19
= 205 m/min

Duration that Barbara's cousin took to jog to the garden
= 8200 ÷ 205
= 40 min

Time that Barbara's cousin left the florist:
40 min before 8 a.m. = 7.20 a.m.

Answer(s): 7.20 a.m.