Lee received $1 from his mother in the 1st week of school and $3 in the 2nd week. Each week, he receives $2 more than the week before.
- How much money did he received in the 11th week?
- In which week did he receive $17?
(a)
Amount that Lee received on 1st Week = $1
Amount that Lee received on 2nd Week = $10
Formula:
Amount received each week = 1 + (Week number - 1) x $2
Amount received on Week 11
= 1 + (11 - 1) x 2
= 1 + 10 x 2
= 1 + 20
= $21
(b)
Week number that Lee received $17
= [(17 - 1) ÷ 2] + 1
= (16 ÷ 2) + 1
= 8 + 1
= 9
Answer(s): (a) $21; (b) 9