Mrs Pang left home at 8 a.m. and drove towards the city. 1²₃ hour later, Mr Pang left the house and drove at an average speed of 103 km/h towards the city. When Mr Pang reached his destination at 2 p.m., Mrs Pang was 22 km away from the city. Find Mrs Pang’s average speed in km/h. Express your answer in mixed number.
1 h = 60 min 
²₃ h = ²₃ x 60 = 40 min
1²₃ = 1 h 40 min

1 h 40 min after 8 a.m. = 9.40 a.m.

Time that Mr Pang left the house = 9.40 a.m.

Time that Mr Pang took from 9.40 a.m. to 2 p.m. to reach his destination = 4 h 20 min

1 min = ¹₆₀ h
20 min = ²⁰₆₀ h = ¹₃ h
4 h 20 min = 4¹₃ h

Distance that Mr Pang drove
= 4¹₃ x 103
= 446¹₃ km

Distance that Mrs Pang drove when Mr Pang reached
= 446¹₃ - 22 
= 424¹₃ km

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

Mrs Pang's average speed
= 424¹₃ ÷ 6
= 70¹³₁₈ km/h

Answer(s): 70¹³₁₈ km/h