Kimberly left home at 11.35 a.m. and drove towards the suburb. 2 hours later, her mother left their home and drove towards the same suburb at 76 km/h. When the mother reached the suburb at 5.35 p.m., Kimberly had another 4 km to travel. What was Kimberly’s average speed? Express your answer in mixed number.
Time that the Kimberly's mother started driving = 1.35 p.m.
Duration that Kimberly's mother drove from 1.35 p.m. to 5.35 p.m. = 4 h

Distance that Kimberly's mother travelled
= 4 x 76
= 304 km

Distance that Kimberly travelled by the time her mother reached the city
= 304 - 4
= 300 km

Time that Kimberly took to travel 300 km = 6 h

Kimberly's average speed
= 300 ÷ 6
= 50 km/h

Answer(s): 50 km/h