John was training for a swimming competition. On Day 1 of his training, he swam 600 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 3 km?
(a)
1000 m = 1 km
600 m = 0.6 km
Pattern for the distance swam
Day 1: ((1 - 1) x 0.1) + 0.6 = 0.6
Day 2: ((2 - 1) x 0.1) + 0.6 = 0.7
Day 3: ((3 - 1) x 0.1) + 0.6 = 0.8
Formula
Distance swam = ((Number of day - 1) x 0.1) + 0.6
Distance swam on Day 10
= [(10 - 1) x 0.1] + 0.6
= 9 x 0.1 + 0.6
= 0.9 + 0.6
= 1.5 km
(b)
Number of days he swam 3 km
= [(3 - 0.6) ÷ 0.1] + 1
= 2.4 ÷ 0.1 + 1
= 24 + 1
= 25
Answer(s): (a) 1.5 km; (b) 25