City Y and City Z are 396 km apart. At 5.45 p.m., Oscar is travelling at a uniform speed left City Y for City Z while Dylan set off from City Z to City Y along the same road at a uniform speed, which was 12 km/h slower than that of Oscar. The two met at 8.45 p.m.

1. Find the speed of Oscar.
2. If Dylan continued to travel at the same speed, how long would it take for him to reach his destination after the two met? Express your answer in mixed number.

(a)
Time taken for Oscar and Dylan to travel from 5.45 p.m. to 8.45 p.m. = 3 h

Average speed of Oscar and Dylan
= 396 ÷ 3
= 132 km/h

Oscar's speed
= (132 + 12) ÷ 2
= 144 ÷ 2 
= 72 km/h

(b)
Dylan's speed
= 72 - 12
= 60 km/h

Distance that Dylan travelled in 3 h
= 3 x 60
= 180 km

Remaining distance that Dylan needed to travel
= 396 - 180
= 216 km

Time that Dylan needed to reach his destination after the two met
= 216 ÷ 60
= 3³⁶₆₀
= 3³₅ h

Answer(s): (a) 72 km/h; (b) 3³₅ h