Shiyun left home at 11.50 a.m. and drove towards the seaside resort. 3 hours later, her auntie left their home and drove towards the same seaside resort at 93 km/h. When the auntie reached the seaside resort at 7.50 p.m., Shiyun had another 5 km to travel. What was Shiyun’s average speed? Express your answer in mixed number.
Time that the Shiyun's auntie started driving = 2.50 p.m.
Duration that Shiyun's auntie drove from 2.50 p.m. to 7.50 p.m. = 5 h

Distance that Shiyun's auntie travelled
= 5 x 93
= 465 km

Distance that Shiyun travelled by the time her auntie reached the city
= 465 - 5
= 460 km

Time that Shiyun took to travel 460 km = 8 h

Shiyun's average speed
= 460 ÷ 8
= 57¹₂ km/h

Answer(s): 57¹₂ km/h