Fabian and Archie took part in a 42 km marathon. Fabian ran half the distance at a speed of 9 km/h and ran slower for the rest of the way at a speed of 6 km/h. Archie ran half his total time at 10 km/h and ran slower for the rest of the time at 10 km/h. If they started the marathon at 5.30 a.m., at what time would each of them finish?
- Fabian
- Archie
(a)
Half of the 42 km marathon = 42 ÷ 2 = 21 km
Time taken by Fabian for the first half of the marathon
= 21 ÷ 9
= 2
13 h
Time taken by Fabian for the last half of the marathon
= 21 ÷ 6
= 3
12 h
Total time taken by Fabian
= 2
13 + 3
12= 5
56 h
1 h = 60 min
56 h =
56 x 60 = 50 min
5
56 h = 5 h 50 min
5 h 50 min after 5.30 a.m. = 11.20 a.m.
Time that Fabian would finish the marathon = 11.20 a.m.
(b)
Time taken by Archie for the first half of the marathon
= 21 ÷ 10
= 2
110 h
Time taken by Archie for the last half of the marathon
= 21 ÷ 10
= 2
110 h
Total time taken by Archie
= 2
110 + 2
110 = 4
210 h
1 h = 60 min
210 h =
210 x 60 = 12 min
4
210 h = 4 h 12 min
4 h 12 min after 5.30 a.m. = 9.42 a.m.
Time that Archie would finish the marathon = 9.42 a.m.
Answer(s): (a) 11.20 a.m.; (b) 9.42 a.m.