City D and City E are 360 km apart. At 5.20 p.m., Gabriel is travelling at a uniform speed left City D for City E while Albert set off from City E to City D along the same road at a uniform speed, which was 6 km/h slower than that of Gabriel. The two met at 8.20 p.m.

1. Find the speed of Gabriel.
2. If Albert 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 Gabriel and Albert to travel from 5.20 p.m. to 8.20 p.m. = 3 h

Average speed of Gabriel and Albert
= 360 ÷ 3
= 120 km/h

Gabriel's speed
= (120 + 6) ÷ 2
= 126 ÷ 2 
= 63 km/h

(b)
Albert's speed
= 63 - 6
= 57 km/h

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

Remaining distance that Albert needed to travel
= 360 - 171
= 189 km

Time that Albert needed to reach his destination after the two met
= 189 ÷ 57
= 3¹⁸₅₇
= 3⁶₁₉ h

Answer(s): (a) 63 km/h; (b) 3⁶₁₉ h