At 11 55, Bobby left Town K for Town L, driving at a speed of 69 km/h. At 12 55, Carl also left Town K for Town L driving at a certain speed. Both of them did not change their speed throughout the journey. At 15 55, both of them passed a grocery store that was 138 km away from Town L. How many minutes earlier did Carl reach Town L than Bobby?

Distance that Bobby travelled
= 4 x 69
= 276 km

Distance between Town K and Town L
= 276 + 138
= 414 km

Since Carl passed the grocery store at the same time as Bobby, it means that Carl travelled 276 km in 3 hours.

Carl's speed during the journey
= 276 ÷ 3
= 92 km/h

Duration that Carl took to reach Town L after passing the grocery store
= 138 ÷ 92
= 1.5 h

Duration that Bobby took to reach Town L after passing the grocery store
= 138 ÷ 69
= 2 h

Difference between the time they took to reach Town L
= 2 - 1.5
= 0.5 h

1 h = 60 min
0.5 h = 0.5 x 60 = 30 min

Carl reached Town L 30 minutes earlier than Bobby.

Answer(s): 30 min