City E and City F is 280 km apart. Jack left City E for City F at 8.00 a.m. travelling at an average speed of 70 km/h. Vaidev left City E later than Jack and caught up with him at 10.00 a.m. Vaidev was travelling at a speed of 112 km/h.
- At what time did Vaidev leave City E?
- How much later did Jack arrive in City F than Vaidev? Express your answer in h as a fraction or mixed number.
(a)
From 8.00 a.m. to 10.00 a.m. = 2 h
Distance that Jack covered when Vaidev caught up with Jack
= 2 x 70
= 140 km
Time that Vaidev took to travel 140 km
= 140 ÷ 112
= 1
14 h
1 h = 60 min
14 h =
14 x 60 = 15 min
1
14 h = 1 h 15 min
Time that Vaidev left City E:
1 h 15 min before 10.00 a.m. = 8.45 a.m.
(b)
Remaining distance that they had to cover to reach City F
= 280 - 140
= 140 km
Duration that Vaidev had to travel before reaching City F
= 140 ÷ 112
= 1
14 h
Duration that Jack had to travel before reaching City F
= 140 ÷ 70
= 2 h
Duration that Jack took to arrive later than Vaidev in City F
= 2 - 1
14=
34 h
Answer(s): (a) 8.45 a.m.; (b)
34 h