Zoe was saving money to buy pens. She saved $6 every 5 days. After saving for 45 days, she went to buy pens that were on sale.
- What was the most number of pens she could buy?
- Zoe wanted to buy 47 pens. How much more did she need to save?
(a)
Number of sets of 5 days
= 45 ÷ 5
= 9
Amount that Zoe saved in 45 days
= 9 x 6
= $54
Maximum number of sets of 7 pens that Zoe could buy
= 54 ÷ 11
= 4 r $10
Remaining amount left after buying sets of 7 pens = $10
Maximum number of sets of 4 pens that Zoe could buy with $10
= 10 ÷ 7
= 1 r $3
Remaining amount left after buying sets of 4 pens = $3
Maximum number of pens that Zoe could buy with $3
= 3 ÷ 3
= 1
Most number of pens that Zoe could buy
= 4 x 7 + 1 x 4 + 1
= 28 + 4 + 1
= 33
(b)
Number of sets of 7 pens that Zoe could buy
= 47 ÷ 7
= 6 r 5
Number of sets of 4 pens that Zoe could buy
= 5 ÷ 4
= 1 r 1
Number of individual pens that Zoe could buy = 1
Amount that Zoe needed to buy 47 pens
= 6 x 11 + 1 x 7 + 3
= 66 + 7 + 3
= $76
Amount that Zoe needed to save more
= 76 - 54
= $22
Answer(s): (a) 33; (b) $22