Penelope was saving money to buy pens. She saved $3 every 4 days. After saving for 72 days, she went to buy pens that were on sale.
- What was the most number of pens she could buy?
- Penelope wanted to buy 45 pens. How much more did she need to save?
(a)
Number of sets of 4 days
= 72 ÷ 4
= 18
Amount that Penelope saved in 72 days
= 18 x 3
= $54
Maximum number of sets of 8 pens that Penelope could buy
= 54 ÷ 11
= 4 r $10
Remaining amount left after buying sets of 8 pens = $10
Maximum number of sets of 4 pens that Penelope could buy with $10
= 10 ÷ 7
= 1 r $3
Remaining amount left after buying sets of 4 pens = $3
Maximum number of pens that Penelope could buy with $3
= 3 ÷ 3
= 1
Most number of pens that Penelope could buy
= 4 x 8 + 1 x 4 + 1
= 32 + 4 + 1
= 37
(b)
Number of sets of 8 pens that Penelope could buy
= 45 ÷ 8
= 5 r 5
Number of sets of 4 pens that Penelope could buy
= 5 ÷ 4
= 1 r 1
Number of individual pens that Penelope could buy = 1
Amount that Penelope needed to buy 45 pens
= 5 x 11 + 1 x 7 + 3
= 55 + 7 + 3
= $65
Amount that Penelope needed to save more
= 65 - 54
= $11
Answer(s): (a) 37; (b) $11
