City U and City V is 468 km apart. Luis left City U for City V at 7.00 a.m. travelling at an average speed of 78 km/h. Elijah left City U later than Luis and caught up with him at 11.00 a.m. Elijah was travelling at a speed of 117 km/h.
- At what time did Elijah leave City U?
- How much later did Luis arrive in City V than Elijah? Express your answer in h as a fraction or mixed number.
(a)
From 7.00 a.m. to 11.00 a.m. = 4 h
Distance that Luis covered when Elijah caught up with Luis
= 4 x 78
= 312 km
Time that Elijah took to travel 312 km
= 312 ÷ 117
= 2
23 h
1 h = 60 min
23 h =
23 x 60 = 40 min
2
23 h = 2 h 40 min
Time that Elijah left City U:
2 h 40 min before 11.00 a.m. = 8.20 a.m.
(b)
Remaining distance that they had to cover to reach City V
= 468 - 312
= 156 km
Duration that Elijah had to travel before reaching City V
= 156 ÷ 117
= 1
13 h
Duration that Luis had to travel before reaching City V
= 156 ÷ 78
= 2 h
Duration that Luis took to arrive later than Elijah in City V
= 2 - 1
13=
23 h
Answer(s): (a) 8.20 a.m.; (b)
23 h