City X and City Y are 363 km apart. At 4.42 p.m., Ethan is travelling at a uniform speed left City X for City Y while Tommy set off from City Y to City X along the same road at a uniform speed, which was 7 km/h slower than that of Ethan. The two met at 7.42 p.m.

1. Find the speed of Ethan.
2. If Tommy 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 Ethan and Tommy to travel from 4.42 p.m. to 7.42 p.m. = 3 h

Average speed of Ethan and Tommy
= 363 ÷ 3
= 121 km/h

Ethan's speed
= (121 + 7) ÷ 2
= 128 ÷ 2 
= 64 km/h

(b)
Tommy's speed
= 64 - 7
= 57 km/h

Distance that Tommy travelled in 3 h
= 3 x 57
= 171 km

Remaining distance that Tommy needed to travel
= 363 - 171
= 192 km

Time that Tommy needed to reach his destination after the two met
= 192 ÷ 57
= 3²¹₅₇
= 3⁷₁₉ h

Answer(s): (a) 64 km/h; (b) 3⁷₁₉ h