Luis was training for a swimming competition. On Day 1 of his training, he swam 700 m. On Day 2, he swam 0.1 km more than Day 1. For each subsequent training session, he swam a distance of 0.1 km more than the previous training session.
- On Day 10 of his training session, how far did he swim? Give your answer in km.
- On which day did he swim a distance of 8 km?
(a)
1000 m = 1 km
700 m = 0.7 km
Pattern for the distance swam
Day 1: ((1 - 1) x 0.1) + 0.7 = 0.7
Day 2: ((2 - 1) x 0.1) + 0.7 = 0.8
Day 3: ((3 - 1) x 0.1) + 0.7 = 0.9
Formula
Distance swam = ((Number of day - 1) x 0.1) + 0.7
Distance swam on Day 10
= [(10 - 1) x 0.1] + 0.7
= 9 x 0.1 + 0.7
= 0.9 + 0.7
= 1.6 km
(b)
Number of days he swam 8 km
= [(8 - 0.7) ÷ 0.1] + 1
= 7.3 ÷ 0.1 + 1
= 73 + 1
= 74
Answer(s): (a) 1.6 km; (b) 74