Ahmad received $4 from his aunt in the 1st week of school and $8 in the 2nd week. Each week, he receives $4 more than the week before.
- How much money did he received in the 20th week?
- In which week did he receive $20?
(a)
Amount that Ahmad received on 1st Week = $4
Amount that Ahmad received on 2nd Week = $19
Formula:
Amount received each week = 4 + (Week number - 1) x $4
Amount received on Week 20
= 4 + (20 - 1) x 4
= 4 + 19 x 4
= 4 + 76
= $80
(b)
Week number that Ahmad received $20
= [(20 - 4) ÷ 4] + 1
= (16 ÷ 4) + 1
= 4 + 1
= 5
Answer(s): (a) $80; (b) 5