Hilda was saving money to buy pens. She saved $8 every 3 days. After saving for 18 days, she went to buy pens that were on sale.
- What was the most number of pens she could buy?
- Hilda wanted to buy 40 pens. How much more did she need to save?
(a)
Number of sets of 3 days
= 18 ÷ 3
= 6
Amount that Hilda saved in 18 days
= 6 x 8
= $48
Maximum number of sets of 7 pens that Hilda could buy
= 48 ÷ 10
= 4 r $8
Remaining amount left after buying sets of 7 pens = $8
Maximum number of sets of 4 pens that Hilda could buy with $8
= 8 ÷ 6
= 1 r $2
Remaining amount left after buying sets of 4 pens = $2
Maximum number of pens that Hilda could buy with $2
= 2 ÷ 2
= 1
Most number of pens that Hilda could buy
= 4 x 7 + 1 x 4 + 1
= 28 + 4 + 1
= 33
(b)
Number of sets of 7 pens that Hilda could buy
= 40 ÷ 7
= 5 r 5
Number of sets of 4 pens that Hilda could buy
= 5 ÷ 4
= 1 r 1
Number of individual pens that Hilda could buy = 1
Amount that Hilda needed to buy 40 pens
= 5 x 10 + 1 x 6 + 2
= 50 + 6 + 2
= $58
Amount that Hilda needed to save more
= 58 - 48
= $10
Answer(s): (a) 33; (b) $10