Xandra was saving money to buy pens. She saved $7 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?
- Xandra 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 Xandra saved in 30 days
= 5 x 7
= $35
Maximum number of sets of 9 pens that Xandra could buy
= 35 ÷ 9
= 3 r $8
Remaining amount left after buying sets of 9 pens = $8
Maximum number of sets of 5 pens that Xandra could buy with $8
= 8 ÷ 6
= 1 r $2
Remaining amount left after buying sets of 5 pens = $2
Maximum number of pens that Xandra could buy with $2
= 2 ÷ 2
= 1
Most number of pens that Xandra could buy
= 3 x 9 + 1 x 5 + 1
= 27 + 5 + 1
= 33
(b)
Number of sets of 9 pens that Xandra could buy
= 42 ÷ 9
= 4 r 6
Number of sets of 5 pens that Xandra could buy
= 6 ÷ 5
= 1 r 1
Number of individual pens that Xandra could buy = 1
Amount that Xandra needed to buy 42 pens
= 4 x 9 + 1 x 6 + 2
= 36 + 6 + 2
= $44
Amount that Xandra needed to save more
= 44 - 35
= $9
Answer(s): (a) 33; (b) $9
