Mrs Lin left home at 10 a.m. and drove towards the city. 1³₄ hour later, Mr Lin left the house and drove at an average speed of 101 km/h towards the city. When Mr Lin reached his destination at 3 p.m., Mrs Lin was 16 km away from the city. Find Mrs Lin’s average speed in km/h. Express your answer in mixed number.
1 h = 60 min 
³₄ h = ³₄ x 60 = 45 min
1³₄ = 1 h 45 min

1 h 45 min after 10 a.m. = 11.45 a.m.

Time that Mr Lin left the house = 11.45 a.m.

Time that Mr Lin took from 11.45 a.m. to 3 p.m. to reach his destination = 3 h 15 min

1 min = ¹₆₀ h
15 min = ¹⁵₆₀ h = ¹₄ h
3 h 15 min = 3¹₄ h

Distance that Mr Lin drove
= 3¹₄ x 101
= 328¹₄ km

Distance that Mrs Lin drove when Mr Lin reached
= 328¹₄ - 16 
= 312¹₄ km

Time that Mrs Lin took to travel from 10 a.m. to 3 p.m. = 5 h

Mrs Lin's average speed
= 312¹₄ ÷ 5
= 62⁹₂₀ km/h

Answer(s): 62⁹₂₀ km/h