Tammy left home at 11.50 a.m. and drove towards the province. 2 hours later, her older sister left their home and drove towards the same province at 95 km/h. When the older sister reached the province at 4.50 p.m., Tammy had another 6 km to travel. What was Tammy’s average speed? Express your answer in mixed number.
Time that the Tammy's older sister started driving = 1.50 p.m.
Duration that Tammy's older sister drove from 1.50 p.m. to 4.50 p.m. = 3 h

Distance that Tammy's older sister travelled
= 3 x 95
= 285 km

Distance that Tammy travelled by the time her older sister reached the city
= 285 - 6
= 279 km

Time that Tammy took to travel 279 km = 5 h

Tammy's average speed
= 279 ÷ 5
= 55⁴₅ km/h

Answer(s): 55⁴₅ km/h