Asher was training for a swimming competition. On Day 1 of his training, he swam 900 m. On Day 2, he swam 0.7 km more than Day 1. For each subsequent training session, he swam a distance of 0.7 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 3 km?
(a)
1000 m = 1 km
900 m = 0.9 km
Pattern for the distance swam
Day 1: ((1 - 1) x 0.7) + 0.9 = 0.9
Day 2: ((2 - 1) x 0.7) + 0.9 = 1.6
Day 3: ((3 - 1) x 0.7) + 0.9 = 2.3
Formula
Distance swam = ((Number of day - 1) x 0.7) + 0.9
Distance swam on Day 9
= [(9 - 1) x 0.7] + 0.9
= 8 x 0.7 + 0.9
= 5.6 + 0.9
= 6.5 km
(b)
Number of days he swam 3 km
= [(3 - 0.9) ÷ 0.7] + 1
= 2.1 ÷ 0.7 + 1
= 3 + 1
= 4
Answer(s): (a) 6.5 km; (b) 4