Elyse was saving money to buy pens. She saved $5 every 7 days. After saving for 28 days, she went to buy pens that were on sale.
- What was the most number of pens she could buy?
- Elyse wanted to buy 41 pens. How much more did she need to save?
(a)
Number of sets of 7 days
= 28 ÷ 7
= 4
Amount that Elyse saved in 28 days
= 4 x 5
= $20
Maximum number of sets of 9 pens that Elyse could buy
= 20 ÷ 7
= 2 r $6
Remaining amount left after buying sets of 9 pens = $6
Maximum number of sets of 5 pens that Elyse could buy with $6
= 6 ÷ 4
= 1 r $2
Remaining amount left after buying sets of 5 pens = $2
Maximum number of pens that Elyse could buy with $2
= 2 ÷ 2
= 1
Most number of pens that Elyse could buy
= 2 x 9 + 1 x 5 + 1
= 18 + 5 + 1
= 24
(b)
Number of sets of 9 pens that Elyse could buy
= 41 ÷ 9
= 4 r 5
Number of sets of 5 pens that Elyse could buy
= 5 ÷ 5
= 1 r 0
Amount that Elyse needed to buy 41 pens
= 4 x 7 + 1 x 4
= 28 + 4
= $32
Amount that Elyse needed to save more
= 32 - 20
= $12
Answer(s): (a) 24; (b) $12