City Q and City R are 363 km apart. At 4.12 p.m., Ivan is travelling at a uniform speed left City Q for City R while Dylan set off from City R to City Q along the same road at a uniform speed, which was 7 km/h slower than that of Ivan. The two met at 7.12 p.m.

1. Find the speed of Ivan.
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 Ivan and Dylan to travel from 4.12 p.m. to 7.12 p.m. = 3 h

Average speed of Ivan and Dylan
= 363 ÷ 3
= 121 km/h

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

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

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

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

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

Answer(s): (a) 64 km/h; (b) 3⁷₁₉ h