Lee received $1 from his aunt 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 7th week?
- In which week did he receive $21?
(a)
Amount that Lee received on 1st Week = $1
Amount that Lee received on 2nd Week = $6
Formula:
Amount received each week = 1 + (Week number - 1) x $2
Amount received on Week 7
= 1 + (7 - 1) x 2
= 1 + 6 x 2
= 1 + 12
= $13
(b)
Week number that Lee received $21
= [(21 - 1) ÷ 2] + 1
= (20 ÷ 2) + 1
= 10 + 1
= 11
Answer(s): (a) $13; (b) 11