Carl received $5 from his mother in the 1st week of school and $9 in the 2nd week. Each week, he receives $4 more than the week before.
- How much money did he received in the 17th week?
- In which week did he receive $25?
(a)
Amount that Carl received on 1st Week = $5
Amount that Carl received on 2nd Week = $16
Formula:
Amount received each week = 5 + (Week number - 1) x $4
Amount received on Week 17
= 5 + (17 - 1) x 4
= 5 + 16 x 4
= 5 + 64
= $69
(b)
Week number that Carl received $25
= [(25 - 5) ÷ 4] + 1
= (20 ÷ 4) + 1
= 5 + 1
= 6
Answer(s): (a) $69; (b) 6