Mrs Choy left home at 8 a.m. and drove towards the city. 2³₄ hour later, Mr Choy left the house and drove at an average speed of 103 km/h towards the city. When Mr Choy reached his destination at 2 p.m., Mrs Choy was 22 km away from the city. Find Mrs Choy’s average speed in km/h. Express your answer in mixed number.
1 h = 60 min 
³₄ h = ³₄ x 60 = 45 min
2³₄ = 2 h 45 min

2 h 45 min after 8 a.m. = 10.45 a.m.

Time that Mr Choy left the house = 10.45 a.m.

Time that Mr Choy took from 10.45 a.m. to 2 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 Choy drove
= 3¹₄ x 103
= 334³₄ km

Distance that Mrs Choy drove when Mr Choy reached
= 334³₄ - 22 
= 312³₄ km

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

Mrs Choy's average speed
= 312³₄ ÷ 6
= 52¹₈ km/h

Answer(s): 52¹₈ km/h