Henry was training for a swimming competition. On Day 1 of his training, he swam 200 m. On Day 2, he swam 0.6 km more than Day 1. For each subsequent training session, he swam a distance of 0.6 km more than the previous training session.
- On Day 7 of his training session, how far did he swim? Give your answer in km.
- On which day did he swim a distance of 5 km?
(a)
1000 m = 1 km
200 m = 0.2 km
Pattern for the distance swam
Day 1: ((1 - 1) x 0.6) + 0.2 = 0.2
Day 2: ((2 - 1) x 0.6) + 0.2 = 0.8
Day 3: ((3 - 1) x 0.6) + 0.2 = 1.4
Formula
Distance swam = ((Number of day - 1) x 0.6) + 0.2
Distance swam on Day 7
= [(7 - 1) x 0.6] + 0.2
= 6 x 0.6 + 0.2
= 3.6 + 0.2
= 3.8 km
(b)
Number of days he swam 5 km
= [(5 - 0.2) ÷ 0.6] + 1
= 4.8 ÷ 0.6 + 1
= 8 + 1
= 9
Answer(s): (a) 3.8 km; (b) 9