City C and City D are 420 km apart. At 3.52 p.m., Jeremy is travelling at a uniform speed left City C for City D while Ryan set off from City D to City C along the same road at a uniform speed, which was 10 km/h slower than that of Jeremy. The two met at 6.52 p.m.

1. Find the speed of Jeremy.
2. If Ryan 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 Jeremy and Ryan to travel from 3.52 p.m. to 6.52 p.m. = 3 h

Average speed of Jeremy and Ryan
= 420 ÷ 3
= 140 km/h

Jeremy's speed
= (140 + 10) ÷ 2
= 150 ÷ 2 
= 75 km/h

(b)
Ryan's speed
= 75 - 10
= 65 km/h

Distance that Ryan travelled in 3 h
= 3 x 65
= 195 km

Remaining distance that Ryan needed to travel
= 420 - 195
= 225 km

Time that Ryan needed to reach his destination after the two met
= 225 ÷ 65
= 3³⁰₆₅
= 3⁶₁₃ h

Answer(s): (a) 75 km/h; (b) 3⁶₁₃ h