Zoe was saving money to buy pens. She saved $4 every 6 days. After saving for 42 days, she went to buy pens that were on sale.
- What was the most number of pens she could buy?
- Zoe wanted to buy 26 pens. How much more did she need to save?
(a)
Number of sets of 6 days
= 42 ÷ 6
= 7
Amount that Zoe saved in 42 days
= 7 x 4
= $28
Maximum number of sets of 7 pens that Zoe could buy
= 28 ÷ 10
= 2 r $8
Remaining amount left after buying sets of 7 pens = $8
Maximum number of sets of 4 pens that Zoe could buy with $8
= 8 ÷ 6
= 1 r $2
Remaining amount left after buying sets of 4 pens = $2
Maximum number of pens that Zoe could buy with $2
= 2 ÷ 2
= 1
Most number of pens that Zoe could buy
= 2 x 7 + 1 x 4 + 1
= 14 + 4 + 1
= 19
(b)
Number of sets of 7 pens that Zoe could buy
= 26 ÷ 7
= 3 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 26 pens
= 3 x 10 + 1 x 6 + 2
= 30 + 6 + 2
= $38
Amount that Zoe needed to save more
= 38 - 28
= $10
Answer(s): (a) 19; (b) $10