Roshel was saving money to buy pens. She saved $5 every 3 days. After saving for 12 days, she went to buy pens that were on sale.
- What was the most number of pens she could buy?
- Roshel wanted to buy 29 pens. How much more did she need to save?
(a)
Number of sets of 3 days
= 12 ÷ 3
= 4
Amount that Roshel saved in 12 days
= 4 x 5
= $20
Maximum number of sets of 8 pens that Roshel could buy
= 20 ÷ 7
= 2 r $6
Remaining amount left after buying sets of 8 pens = $6
Maximum number of sets of 4 pens that Roshel could buy with $6
= 6 ÷ 4
= 1 r $2
Remaining amount left after buying sets of 4 pens = $2
Maximum number of pens that Roshel could buy with $2
= 2 ÷ 2
= 1
Most number of pens that Roshel could buy
= 2 x 8 + 1 x 4 + 1
= 16 + 4 + 1
= 21
(b)
Number of sets of 8 pens that Roshel could buy
= 29 ÷ 8
= 3 r 5
Number of sets of 4 pens that Roshel could buy
= 5 ÷ 4
= 1 r 1
Number of individual pens that Roshel could buy = 1
Amount that Roshel needed to buy 29 pens
= 3 x 7 + 1 x 4 + 2
= 21 + 4 + 2
= $27
Amount that Roshel needed to save more
= 27 - 20
= $7
Answer(s): (a) 21; (b) $7
