Sabrina was saving money to buy pens. She saved $9 every 8 days. After saving for 48 days, she went to buy pens that were on sale.
- What was the most number of pens she could buy?
- Sabrina wanted to buy 39 pens. How much more did she need to save?
(a)
Number of sets of 8 days
= 48 ÷ 8
= 6
Amount that Sabrina saved in 48 days
= 6 x 9
= $54
Maximum number of sets of 7 pens that Sabrina could buy
= 54 ÷ 11
= 4 r $10
Remaining amount left after buying sets of 7 pens = $10
Maximum number of sets of 4 pens that Sabrina could buy with $10
= 10 ÷ 7
= 1 r $3
Remaining amount left after buying sets of 4 pens = $3
Maximum number of pens that Sabrina could buy with $3
= 3 ÷ 3
= 1
Most number of pens that Sabrina could buy
= 4 x 7 + 1 x 4 + 1
= 28 + 4 + 1
= 33
(b)
Number of sets of 7 pens that Sabrina could buy
= 39 ÷ 7
= 5 r 4
Number of sets of 4 pens that Sabrina could buy
= 4 ÷ 4
= 1 r 0
Amount that Sabrina needed to buy 39 pens
= 5 x 11 + 1 x 7
= 55 + 7
= $62
Amount that Sabrina needed to save more
= 62 - 54
= $8
Answer(s): (a) 33; (b) $8
