Mrs Tang left home at 8 a.m. and drove towards the city. 2¹₂ hour later, Mr Tang left the house and drove at an average speed of 96 km/h towards the city. When Mr Tang reached his destination at 2 p.m., Mrs Tang was 17 km away from the city. Find Mrs Tang’s average speed in km/h. Express your answer in mixed number.
1 h = 60 min 
¹₂ h = ¹₂ x 60 = 30 min
2¹₂ = 2 h 30 min

2 h 30 min after 8 a.m. = 10.30 a.m.

Time that Mr Tang left the house = 10.30 a.m.

Time that Mr Tang took from 10.30 a.m. to 2 p.m. to reach his destination = 3 h 30 min

1 min = ¹₆₀ h
30 min = ³⁰₆₀ h = ¹₂ h
3 h 30 min = 3¹₂ h

Distance that Mr Tang drove
= 3¹₂ x 96
= 336 km

Distance that Mrs Tang drove when Mr Tang reached
= 336 - 17 
= 319 km

Time that Mrs Tang took to travel from 8 a.m. to 2 p.m. = 6 h

Mrs Tang's average speed
= 319 ÷ 6
= 53¹₆ km/h

Answer(s): 53¹₆ km/h