City K and City L are 580 km apart. At 2.14 p.m., Albert is travelling at a uniform speed left City K for City L while Luis set off from City L to City K along the same road at a uniform speed, which was 9 km/h slower than that of Albert. The two met at 6.14 p.m.
- Find the speed of Albert.
- If Luis 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 Albert and Luis to travel from 2.14 p.m. to 6.14 p.m. = 4 h
Average speed of Albert and Luis
= 580 ÷ 4
= 145 km/h
Albert's speed
= (145 + 9) ÷ 2
= 154 ÷ 2
= 77 km/h
(b)
Luis's speed
= 77 - 9
= 68 km/h
Distance that Luis travelled in 4 h
= 4 x 68
= 272 km
Remaining distance that Luis needed to travel
= 580 - 272
= 308 km
Time that Luis needed to reach his destination after the two met
= 308 ÷ 68
= 4
3668 = 4
917 h
Answer(s): (a) 77 km/h; (b) 4
917 h