City A and City B are 540 km apart. At 2.33 p.m., Liam is travelling at a uniform speed left City A for City B while Japheth set off from City B to City A along the same road at a uniform speed, which was 7 km/h slower than that of Liam. The two met at 6.33 p.m.

1. Find the speed of Liam.
2. If Japheth 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 Liam and Japheth to travel from 2.33 p.m. to 6.33 p.m. = 4 h

Average speed of Liam and Japheth
= 540 ÷ 4
= 135 km/h

Liam's speed
= (135 + 7) ÷ 2
= 142 ÷ 2 
= 71 km/h

(b)
Japheth's speed
= 71 - 7
= 64 km/h

Distance that Japheth travelled in 4 h
= 4 x 64
= 256 km

Remaining distance that Japheth needed to travel
= 540 - 256
= 284 km

Time that Japheth needed to reach his destination after the two met
= 284 ÷ 64
= 4²⁸₆₄
= 4⁷₁₆ h

Answer(s): (a) 71 km/h; (b) 4⁷₁₆ h