Erika was saving money to buy pens. She saved $8 every 6 days. After saving for 24 days, she went to buy pens that were on sale.
- What was the most number of pens she could buy?
- Erika wanted to buy 32 pens. How much more did she need to save?
(a)
Number of sets of 6 days
= 24 ÷ 6
= 4
Amount that Erika saved in 24 days
= 4 x 8
= $32
Maximum number of sets of 7 pens that Erika could buy
= 32 ÷ 11
= 2 r $10
Remaining amount left after buying sets of 7 pens = $10
Maximum number of sets of 3 pens that Erika could buy with $10
= 10 ÷ 6
= 1 r $4
Remaining amount left after buying sets of 3 pens = $4
Maximum number of pens that Erika could buy with $4
= 4 ÷ 4
= 1
Most number of pens that Erika could buy
= 2 x 7 + 1 x 3 + 1
= 14 + 3 + 1
= 18
(b)
Number of sets of 7 pens that Erika could buy
= 32 ÷ 7
= 4 r 4
Number of sets of 3 pens that Erika could buy
= 4 ÷ 3
= 1 r 1
Number of individual pens that Erika could buy = 1
Amount that Erika needed to buy 32 pens
= 4 x 11 + 1 x 6 + 4
= 44 + 6 + 4
= $54
Amount that Erika needed to save more
= 54 - 32
= $22
Answer(s): (a) 18; (b) $22