Bryan and Caden took part in a 24 km marathon. Bryan ran half the distance at a speed of 8 km/h and ran slower for the rest of the way at a speed of 5 km/h. Caden 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 6.30 a.m., at what time would each of them finish?
- Bryan
- Caden
(a)
Half of the 24 km marathon = 24 ÷ 2 = 12 km
Time taken by Bryan for the first half of the marathon
= 12 ÷ 8
= 1
12 h
Time taken by Bryan for the last half of the marathon
= 12 ÷ 5
= 2
25 h
Total time taken by Bryan
= 1
12 + 2
25= 3
910 h
1 h = 60 min
910 h =
910 x 60 = 54 min
3
910 h = 3 h 54 min
3 h 54 min after 6.30 a.m. = 10.24 a.m.
Time that Bryan would finish the marathon = 10.24 a.m.
(b)
Time taken by Caden for the first half of the marathon
= 12 ÷ 10
= 1
15 h
Time taken by Caden for the last half of the marathon
= 12 ÷ 10
= 1
15 h
Total time taken by Caden
= 1
15 + 1
15 = 2
25 h
1 h = 60 min
25 h =
25 x 60 = 24 min
2
25 h = 2 h 24 min
2 h 24 min after 6.30 a.m. = 8.54 a.m.
Time that Caden would finish the marathon = 8.54 a.m.
Answer(s): (a) 10.24 a.m.; (b) 8.54 a.m.