City M and City N is 350 km apart. Xavier left City M for City N at 9.00 a.m. travelling at an average speed of 70 km/h. Riordan left City M later than Xavier and caught up with him at 12.00 p.m. Riordan was travelling at a speed of 90 km/h.
- At what time did Riordan leave City M?
- How much later did Xavier arrive in City N than Riordan? Express your answer in h as a fraction or mixed number.
(a)
From 9.00 a.m. to 12.00 p.m. = 3 h
Distance that Xavier covered when Riordan caught up with Xavier
= 3 x 70
= 210 km
Time that Riordan took to travel 210 km
= 210 ÷ 90
= 2
13 h
1 h = 60 min
13 h =
13 x 60 = 20 min
2
13 h = 2 h 20 min
Time that Riordan left City M:
2 h 20 min before 12.00 p.m. = 9.40 a.m.
(b)
Remaining distance that they had to cover to reach City N
= 350 - 210
= 140 km
Duration that Riordan had to travel before reaching City N
= 140 ÷ 90
= 1
59 h
Duration that Xavier had to travel before reaching City N
= 140 ÷ 70
= 2 h
Duration that Xavier took to arrive later than Riordan in City N
= 2 - 1
59=
49 h
Answer(s): (a) 9.40 a.m.; (b)
49 h