Roshel was saving money to buy pens. She saved $4 every 6 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?
- Roshel wanted to buy 42 pens. How much more did she need to save?
(a)
Number of sets of 6 days
= 30 ÷ 6
= 5
Amount that Roshel saved in 30 days
= 5 x 4
= $20
Maximum number of sets of 9 pens that Roshel could buy
= 20 ÷ 7
= 2 r $6
Remaining amount left after buying sets of 9 pens = $6
Maximum number of sets of 5 pens that Roshel could buy with $6
= 6 ÷ 4
= 1 r $2
Remaining amount left after buying sets of 5 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 9 + 1 x 5 + 1
= 18 + 5 + 1
= 24
(b)
Number of sets of 9 pens that Roshel could buy
= 42 ÷ 9
= 4 r 6
Number of sets of 5 pens that Roshel could buy
= 6 ÷ 5
= 1 r 1
Number of individual pens that Roshel could buy = 1
Amount that Roshel needed to buy 42 pens
= 4 x 7 + 1 x 4 + 2
= 28 + 4 + 2
= $34
Amount that Roshel needed to save more
= 34 - 20
= $14
Answer(s): (a) 24; (b) $14