Adam saves $2 in the 1st week and $8 in the 2nd week.
Each week, he saves $6 more than the week before.
- How much money does he save in the 8th week?
- In which week does he save $44?
(a)
Amount that Adam saves on Week 1: $2
Amount that Adam saves on Week 2: $8 = 2 + 6 = 2 + (6 x 1)
Amount that Adam saves on Week 3: $14 = 2 + 6 + 6 = 2 + (6 x 2)
Amount that Adam saves on a certain week = 2 +(6 x (Week number - 1))
Amount that Adam saves on Week 8
= 2 + 6 × (8 - 1)
= 2 + 6 × 7
= 2 + 42
= $44
(b)
2 + 6 x (Week number - 1) = 44
6 x (Week number - 2) = 44 - 2
6 x (Week number - 2) = 42
Week number - 1 = 42 ÷ 6
Week number - 1 = 7
Week number = 7 + 1
Week number = 8
Answer(s): (a) $44; (b) 8