Joelle was saving money to buy pens. She saved $5 every 3 days. After saving for 21 days, she went to buy pens that were on sale.
- What was the most number of pens she could buy?
- Joelle wanted to buy 37 pens. How much more did she need to save?
(a)
Number of sets of 3 days
= 21 ÷ 3
= 7
Amount that Joelle saved in 21 days
= 7 x 5
= $35
Maximum number of sets of 8 pens that Joelle could buy
= 35 ÷ 9
= 3 r $8
Remaining amount left after buying sets of 8 pens = $8
Maximum number of sets of 5 pens that Joelle could buy with $8
= 8 ÷ 6
= 1 r $2
Remaining amount left after buying sets of 5 pens = $2
Maximum number of pens that Joelle could buy with $2
= 2 ÷ 2
= 1
Most number of pens that Joelle could buy
= 3 x 8 + 1 x 5 + 1
= 24 + 5 + 1
= 30
(b)
Number of sets of 8 pens that Joelle could buy
= 37 ÷ 8
= 4 r 5
Number of sets of 5 pens that Joelle could buy
= 5 ÷ 5
= 1 r 0
Amount that Joelle needed to buy 37 pens
= 4 x 9 + 1 x 6
= 36 + 6
= $42
Amount that Joelle needed to save more
= 42 - 35
= $7
Answer(s): (a) 30; (b) $7