Yen was saving money to buy pens. She saved $5 every 6 days. After saving for 42 days, she went to buy pens that were on sale.
- What was the most number of pens she could buy?
- Yen wanted to buy 44 pens. How much more did she need to save?
(a)
Number of sets of 6 days
= 42 ÷ 6
= 7
Amount that Yen saved in 42 days
= 7 x 5
= $35
Maximum number of sets of 8 pens that Yen could buy
= 35 ÷ 9
= 3 r $8
Remaining amount left after buying sets of 8 pens = $8
Maximum number of sets of 4 pens that Yen could buy with $8
= 8 ÷ 5
= 1 r $3
Remaining amount left after buying sets of 4 pens = $3
Maximum number of pens that Yen could buy with $3
= 3 ÷ 3
= 1
Most number of pens that Yen could buy
= 3 x 8 + 1 x 4 + 1
= 24 + 4 + 1
= 29
(b)
Number of sets of 8 pens that Yen could buy
= 44 ÷ 8
= 5 r 4
Number of sets of 4 pens that Yen could buy
= 4 ÷ 4
= 1 r 0
Amount that Yen needed to buy 44 pens
= 5 x 9 + 1 x 5
= 45 + 5
= $50
Amount that Yen needed to save more
= 50 - 35
= $15
Answer(s): (a) 29; (b) $15
