Gillian left home at 11.55 a.m. and drove towards the seaside resort. 2 hours later, her grandfather left their home and drove towards the same seaside resort at 95 km/h. When the grandfather reached the seaside resort at 6.55 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 grandfather started driving = 1.55 p.m.
Duration that Gillian's grandfather drove from 1.55 p.m. to 6.55 p.m. = 5 h

Distance that Gillian's grandfather travelled
= 5 x 95
= 475 km

Distance that Gillian travelled by the time her grandfather reached the city
= 475 - 6
= 469 km

Time that Gillian took to travel 469 km = 7 h

Gillian's average speed
= 469 ÷ 7
= 67 km/h

Answer(s): 67 km/h