City G and City H are 492 km apart. At 1.25 p.m., Charlie is travelling at a uniform speed left City G for City H while Dylan set off from City H to City G along the same road at a uniform speed, which was 11 km/h slower than that of Charlie. The two met at 5.25 p.m.

1. Find the speed of Charlie.
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 Charlie and Dylan to travel from 1.25 p.m. to 5.25 p.m. = 4 h

Average speed of Charlie and Dylan
= 492 ÷ 4
= 123 km/h

Charlie's speed
= (123 + 11) ÷ 2
= 134 ÷ 2 
= 67 km/h

(b)
Dylan's speed
= 67 - 11
= 56 km/h

Distance that Dylan travelled in 4 h
= 4 x 56
= 224 km

Remaining distance that Dylan needed to travel
= 492 - 224
= 268 km

Time that Dylan needed to reach his destination after the two met
= 268 ÷ 56
= 4⁴⁴₅₆
= 4¹¹₁₄ h

Answer(s): (a) 67 km/h; (b) 4¹¹₁₄ h