After cycling for 23 km, Billy took a break before he continued cycling ¹₅ of the remaining distance. He then realised that he still had ¹₇ of the total distance not completed. If Billy's average speed was 20 km/h, how much time did he take to complete the entire ride? Express your answer in mixed number.
Fraction of the remaining distance to cycle after resting
= 1 - ¹₅ 
= ⁴₅

⁴₅ of the remaining distance = ¹₇ of the total distance
⁴₅ of the remaining distance = ⁴₂₈ of the total distance

Total distance = 28 u

28 u - 4 u = 1 u + 23
24 u - 1 u = 23
23 u = 23
1 u = 23 ÷ 23 = 1

Total distance
= 28 x 1
= 28 km

Time taken by Billy to travel the entire distance
= 28 ÷ 20
= 1 ⁸₂₀
= 1²₅ h

Answer(s): 1²₅ h