City K and City L are 411 km apart. At 3.44 p.m., Rael is travelling at a uniform speed left City K for City L while Liam set off from City L to City K along the same road at a uniform speed, which was 11 km/h slower than that of Rael. The two met at 6.44 p.m.
- Find the speed of Rael.
- If Liam 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 Rael and Liam to travel from 3.44 p.m. to 6.44 p.m. = 3 h
Average speed of Rael and Liam
= 411 ÷ 3
= 137 km/h
Rael's speed
= (137 + 11) ÷ 2
= 148 ÷ 2
= 74 km/h
(b)
Liam's speed
= 74 - 11
= 63 km/h
Distance that Liam travelled in 3 h
= 3 x 63
= 189 km
Remaining distance that Liam needed to travel
= 411 - 189
= 222 km
Time that Liam needed to reach his destination after the two met
= 222 ÷ 63
= 3
3363 = 3
1121 h
Answer(s): (a) 74 km/h; (b) 3
1121 h