City V and City W are 405 km apart. At 5.34 p.m., Carl is travelling at a uniform speed left City V for City W while Charlie set off from City W to City V along the same road at a uniform speed, which was 9 km/h slower than that of Carl. The two met at 8.34 p.m.

1. Find the speed of Carl.
2. If Charlie 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 Carl and Charlie to travel from 5.34 p.m. to 8.34 p.m. = 3 h

Average speed of Carl and Charlie
= 405 ÷ 3
= 135 km/h

Carl's speed
= (135 + 9) ÷ 2
= 144 ÷ 2 
= 72 km/h

(b)
Charlie's speed
= 72 - 9
= 63 km/h

Distance that Charlie travelled in 3 h
= 3 x 63
= 189 km

Remaining distance that Charlie needed to travel
= 405 - 189
= 216 km

Time that Charlie needed to reach his destination after the two met
= 216 ÷ 63
= 3²⁷₆₃
= 3³₇ h

Answer(s): (a) 72 km/h; (b) 3³₇ h