Gillian left home at 10.35 a.m. and drove towards the city. 3 hours later, her cousin left their home and drove towards the same city at 96 km/h. When the cousin reached the city at 5.35 p.m., Gillian had another 6 km to travel. What was Gillian’s average speed? Express your answer in mixed number.
Time that the Gillian's cousin started driving = 1.35 p.m.
Duration that Gillian's cousin drove from 1.35 p.m. to 5.35 p.m. = 4 h

Distance that Gillian's cousin travelled
= 4 x 96
= 384 km

Distance that Gillian travelled by the time her cousin reached the city
= 384 - 6
= 378 km

Time that Gillian took to travel 378 km = 7 h

Gillian's average speed
= 378 ÷ 7
= 54 km/h

Answer(s): 54 km/h