John received $5 from his mother in the 1st week of school and $7 in the 2nd week. Each week, he receives $2 more than the week before.
- How much money did he received in the 13th week?
- In which week did he receive $17?
(a)
Amount that John received on 1st Week = $5
Amount that John received on 2nd Week = $12
Formula:
Amount received each week = 5 + (Week number - 1) x $2
Amount received on Week 13
= 5 + (13 - 1) x 2
= 5 + 12 x 2
= 5 + 24
= $29
(b)
Week number that John received $17
= [(17 - 5) ÷ 2] + 1
= (12 ÷ 2) + 1
= 6 + 1
= 7
Answer(s): (a) $29; (b) 7