City H and City J are 399 km apart. At 6.22 p.m., Riordan is travelling at a uniform speed left City H for City J while Reggie set off from City J to City H along the same road at a uniform speed, which was 7 km/h slower than that of Riordan. The two met at 9.22 p.m.

1. Find the speed of Riordan.
2. If Reggie 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 Riordan and Reggie to travel from 6.22 p.m. to 9.22 p.m. = 3 h

Average speed of Riordan and Reggie
= 399 ÷ 3
= 133 km/h

Riordan's speed
= (133 + 7) ÷ 2
= 140 ÷ 2 
= 70 km/h

(b)
Reggie's speed
= 70 - 7
= 63 km/h

Distance that Reggie travelled in 3 h
= 3 x 63
= 189 km

Remaining distance that Reggie needed to travel
= 399 - 189
= 210 km

Time that Reggie needed to reach his destination after the two met
= 210 ÷ 63
= 3²¹₆₃
= 3¹₃ h

Answer(s): (a) 70 km/h; (b) 3¹₃ h