Eric was training for a swimming competition. On Day 1 of his training, he swam 700 m. On Day 2, he swam 0.9 km more than Day 1. For each subsequent training session, he swam a distance of 0.9 km more than the previous training session.
- On Day 6 of his training session, how far did he swim? Give your answer in km.
- On which day did he swim a distance of 7 km?
(a)
1000 m = 1 km
700 m = 0.7 km
Pattern for the distance swam
Day 1: ((1 - 1) x 0.9) + 0.7 = 0.7
Day 2: ((2 - 1) x 0.9) + 0.7 = 1.6
Day 3: ((3 - 1) x 0.9) + 0.7 = 2.5
Formula
Distance swam = ((Number of day - 1) x 0.9) + 0.7
Distance swam on Day 6
= [(6 - 1) x 0.9] + 0.7
= 5 x 0.9 + 0.7
= 4.5 + 0.7
= 5.2 km
(b)
Number of days he swam 7 km
= [(7 - 0.7) ÷ 0.9] + 1
= 6.3 ÷ 0.9 + 1
= 7 + 1
= 8
Answer(s): (a) 5.2 km; (b) 8