Adam saves $2 in the 1st week and $6 in the 2nd week.
Each week, he saves $4 more than the week before.
- How much money does he save in the 7th week?
- In which week does he save $58?
(a)
Amount that Adam saves on Week 1: $2
Amount that Adam saves on Week 2: $6 = 2 + 4 = 2 + (4 x 1)
Amount that Adam saves on Week 3: $10 = 2 + 4 + 4 = 2 + (4 x 2)
Amount that Adam saves on a certain week = 2 +(4 x (Week number - 1))
Amount that Adam saves on Week 7
= 2 + 4 × (7 - 1)
= 2 + 4 × 6
= 2 + 24
= $26
(b)
2 + 4 x (Week number - 1) = 58
4 x (Week number - 2) = 58 - 2
4 x (Week number - 2) = 56
Week number - 1 = 56 ÷ 4
Week number - 1 = 14
Week number = 14 + 1
Week number = 15
Answer(s): (a) $26; (b) 15
