Nora left home at 10.50 a.m. and drove towards the countryside. 3 hours later, her auntie left their home and drove towards the same countryside at 99 km/h. When the auntie reached the countryside at 6.50 p.m., Nora had another 3 km to travel. What was Nora’s average speed? Express your answer in mixed number.
Time that the Nora's auntie started driving = 1.50 p.m.
Duration that Nora's auntie drove from 1.50 p.m. to 6.50 p.m. = 5 h

Distance that Nora's auntie travelled
= 5 x 99
= 495 km

Distance that Nora travelled by the time her auntie reached the city
= 495 - 3
= 492 km

Time that Nora took to travel 492 km = 8 h

Nora's average speed
= 492 ÷ 8
= 61¹₂ km/h

Answer(s): 61¹₂ km/h