Howard was training for a swimming competition. On Day 1 of his training, he swam 800 m. On Day 2, he swam 0.2 km more than Day 1. For each subsequent training session, he swam a distance of 0.2 km more than the previous training session.
- On Day 9 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
800 m = 0.8 km
Pattern for the distance swam
Day 1: ((1 - 1) x 0.2) + 0.8 = 0.8
Day 2: ((2 - 1) x 0.2) + 0.8 = 1
Day 3: ((3 - 1) x 0.2) + 0.8 = 1.2
Formula
Distance swam = ((Number of day - 1) x 0.2) + 0.8
Distance swam on Day 9
= [(9 - 1) x 0.2] + 0.8
= 8 x 0.2 + 0.8
= 1.6 + 0.8
= 2.4 km
(b)
Number of days he swam 5 km
= [(5 - 0.8) ÷ 0.2] + 1
= 4.2 ÷ 0.2 + 1
= 21 + 1
= 22
Answer(s): (a) 2.4 km; (b) 22