Mrs Choo left home at 7 a.m. and drove towards the city. 2¹₄ hour later, Mr Choo left the house and drove at an average speed of 97 km/h towards the city. When Mr Choo reached his destination at 1 p.m., Mrs Choo was 12 km away from the city. Find Mrs Choo’s average speed in km/h. Express your answer in mixed number.
1 h = 60 min 
¹₄ h = ¹₄ x 60 = 15 min
2¹₄ = 2 h 15 min

2 h 15 min after 7 a.m. = 9.15 a.m.

Time that Mr Choo left the house = 9.15 a.m.

Time that Mr Choo took from 9.15 a.m. to 1 p.m. to reach his destination = 3 h 45 min

1 min = ¹₆₀ h
45 min = ⁴⁵₆₀ h = ³₄ h
3 h 45 min = 3³₄ h

Distance that Mr Choo drove
= 3³₄ x 97
= 363³₄ km

Distance that Mrs Choo drove when Mr Choo reached
= 363³₄ - 12 
= 351³₄ km

Time that Mrs Choo took to travel from 7 a.m. to 1 p.m. = 6 h

Mrs Choo's average speed
= 351³₄ ÷ 6
= 58⁵₈ km/h

Answer(s): 58⁵₈ km/h