Riordan received $3 from his mother in the 1st week of school and $6 in the 2nd week. Each week, he receives $3 more than the week before.
- How much money did he received in the 16th week?
- In which week did he receive $27?
(a)
Amount that Riordan received on 1st Week = $3
Amount that Riordan received on 2nd Week = $15
Formula:
Amount received each week = 3 + (Week number - 1) x $3
Amount received on Week 16
= 3 + (16 - 1) x 3
= 3 + 15 x 3
= 3 + 45
= $48
(b)
Week number that Riordan received $27
= [(27 - 3) ÷ 3] + 1
= (24 ÷ 3) + 1
= 8 + 1
= 9
Answer(s): (a) $48; (b) 9