Gillian was saving money to buy pens. She saved $4 every 5 days. After saving for 30 days, she went to buy pens that were on sale.
- What was the most number of pens she could buy?
- Gillian wanted to buy 24 pens. How much more did she need to save?
(a)
Number of sets of 5 days
= 30 ÷ 5
= 6
Amount that Gillian saved in 30 days
= 6 x 4
= $24
Maximum number of sets of 7 pens that Gillian could buy
= 24 ÷ 9
= 2 r $6
Remaining amount left after buying sets of 7 pens = $6
Maximum number of sets of 3 pens that Gillian could buy with $6
= 6 ÷ 4
= 1 r $2
Remaining amount left after buying sets of 3 pens = $2
Maximum number of pens that Gillian could buy with $2
= 2 ÷ 2
= 1
Most number of pens that Gillian could buy
= 2 x 7 + 1 x 3 + 1
= 14 + 3 + 1
= 18
(b)
Number of sets of 7 pens that Gillian could buy
= 24 ÷ 7
= 3 r 3
Number of sets of 3 pens that Gillian could buy
= 3 ÷ 3
= 1 r 0
Amount that Gillian needed to buy 24 pens
= 3 x 9 + 1 x 4
= 27 + 4
= $31
Amount that Gillian needed to save more
= 31 - 24
= $7
Answer(s): (a) 18; (b) $7