Ivory was saving money to buy pens. She saved $7 every 8 days. After saving for 40 days, she went to buy pens that were on sale.
- What was the most number of pens she could buy?
- Ivory wanted to buy 25 pens. How much more did she need to save?
(a)
Number of sets of 8 days
= 40 ÷ 8
= 5
Amount that Ivory saved in 40 days
= 5 x 7
= $35
Maximum number of sets of 7 pens that Ivory could buy
= 35 ÷ 12
= 2 r $11
Remaining amount left after buying sets of 7 pens = $11
Maximum number of sets of 3 pens that Ivory could buy with $11
= 11 ÷ 7
= 1 r $4
Remaining amount left after buying sets of 3 pens = $4
Maximum number of pens that Ivory could buy with $4
= 4 ÷ 4
= 1
Most number of pens that Ivory could buy
= 2 x 7 + 1 x 3 + 1
= 14 + 3 + 1
= 18
(b)
Number of sets of 7 pens that Ivory could buy
= 25 ÷ 7
= 3 r 4
Number of sets of 3 pens that Ivory could buy
= 4 ÷ 3
= 1 r 1
Number of individual pens that Ivory could buy = 1
Amount that Ivory needed to buy 25 pens
= 3 x 12 + 1 x 7 + 4
= 36 + 7 + 4
= $47
Amount that Ivory needed to save more
= 47 - 35
= $12
Answer(s): (a) 18; (b) $12