Marion was saving money to buy pens. She saved $3 every 8 days. After saving for 104 days, she went to buy pens that were on sale.
- What was the most number of pens she could buy?
- Marion wanted to buy 51 pens. How much more did she need to save?
(a)
Number of sets of 8 days
= 104 ÷ 8
= 13
Amount that Marion saved in 104 days
= 13 x 3
= $39
Maximum number of sets of 9 pens that Marion could buy
= 39 ÷ 10
= 3 r $9
Remaining amount left after buying sets of 9 pens = $9
Maximum number of sets of 5 pens that Marion could buy with $9
= 9 ÷ 6
= 1 r $3
Remaining amount left after buying sets of 5 pens = $3
Maximum number of pens that Marion could buy with $3
= 3 ÷ 3
= 1
Most number of pens that Marion could buy
= 3 x 9 + 1 x 5 + 1
= 27 + 5 + 1
= 33
(b)
Number of sets of 9 pens that Marion could buy
= 51 ÷ 9
= 5 r 6
Number of sets of 5 pens that Marion could buy
= 6 ÷ 5
= 1 r 1
Number of individual pens that Marion could buy = 1
Amount that Marion needed to buy 51 pens
= 5 x 10 + 1 x 6 + 3
= 50 + 6 + 3
= $59
Amount that Marion needed to save more
= 59 - 39
= $20
Answer(s): (a) 33; (b) $20