Fiona left home at 11.10 a.m. and drove towards the town. 2 hours later, her auntie left their home and drove towards the same town at 83 km/h. When the auntie reached the town at 5.10 p.m., Fiona had another 5 km to travel. What was Fiona’s average speed? Express your answer in mixed number.
Time that the Fiona's auntie started driving = 1.10 p.m.
Duration that Fiona's auntie drove from 1.10 p.m. to 5.10 p.m. = 4 h

Distance that Fiona's auntie travelled
= 4 x 83
= 332 km

Distance that Fiona travelled by the time her auntie reached the city
= 332 - 5
= 327 km

Time that Fiona took to travel 327 km = 6 h

Fiona's average speed
= 327 ÷ 6
= 54¹₂ km/h

Answer(s): 54¹₂ km/h