Mrs Yong left home at 10 a.m. and drove towards the city. 1¹₆ hour later, Mr Yong left the house and drove at an average speed of 103 km/h towards the city. When Mr Yong reached his destination at 1 p.m., Mrs Yong was 30 km away from the city. Find Mrs Yong’s average speed in km/h. Express your answer in mixed number.
1 h = 60 min 
¹₆ h = ¹₆ x 60 = 10 min
1¹₆ = 1 h 10 min

1 h 10 min after 10 a.m. = 11.10 a.m.

Time that Mr Yong left the house = 11.10 a.m.

Time that Mr Yong took from 11.10 a.m. to 1 p.m. to reach his destination = 1 h 50 min

1 min = ¹₆₀ h
50 min = ⁵⁰₆₀ h = ⁵₆ h
1 h 50 min = 1⁵₆ h

Distance that Mr Yong drove
= 1⁵₆ x 103
= 188⁵₆ km

Distance that Mrs Yong drove when Mr Yong reached
= 188⁵₆ - 30 
= 158⁵₆ km

Time that Mrs Yong took to travel from 10 a.m. to 1 p.m. = 3 h

Mrs Yong's average speed
= 158⁵₆ ÷ 3
= 52¹⁷₁₈ km/h

Answer(s): 52¹⁷₁₈ km/h