Cody started driving from City Q towards City R at 15 30 at an average speed of 60 km/h. Riordan began driving from City Q towards City R at 17 20 at an average speed of 110 km/h.

1. At what time did Riordan pass Cody on the road?
2. 1¹₁₀ hours after passing Cody, Riordan reached City R. At what time did Cody reach City R?

(a)
From 15 30 to 17 20 = 1 h 50 min

Time that Cody travelled before Riordan started driving = 1 h 50 min

1 h = 60 min
1 h 50 min = 1⁵⁰₆₀ h = 1⁵₆ h

Distance that Cody travelled before Riordan started driving
= 1⁵₆ x 60
= ¹¹₆ x 60
= 110 km

Difference between Riordan's and Cody's speed
= 110 - 60
= 50 km/h

Time that Riordan took to catch up with Cody
= 110 ÷ 50
= 2.2 h
= 2 h 12 min

2 h 12 min after 17 20 = 19 32

Time that Riordan passed Cody on the road = 19 32

(b)
1¹₁₀ h = 1 h 6 min

Total time that Riordan travelled
= 1 h 6 min + 2 h 12 min
= 3 h 18 min

3 h 18 min = 3¹⁸₆₀h = 3³₁₀h

Distance between City Q and City R
= 3³₁₀ x 110
= 363 km

Time that Cody travelled from City Q to City R
= 363 ÷ 60
= 6.05 h
= 6 h 3 min

6 h 3 min after 15 30 = 21 33

Time that Cody reached City R = 21 33

Answer: (a) 19 32; (b) 21 33