Abi spent
34 of her money on 15 pens and 7 pencils. The cost of each pencil is 3 times the cost of each pen. She bought some more pens with
12 of her remaining money. How many pens did Abi buy altogether?
15 pens + 7 pencils |
Remaining amount |
Total amount |
3 p = 36 u |
1 p = 12 u |
4 p |
15 pens |
7 pencils |
More pens |
Left |
|
|
|
1 |
1 |
|
15 u |
21 u |
6 u |
|
|
Cost of 1 pen = 1 u
Cost of 1 pencil = 3 u
Cost of 15 pens = 15 x 1 u = 15 u
Cost of 7 pencils = 7 x 3 u = 21 u
Cost of 15 pens + 7 pencils
= 15 u + 21 u
= 36 u
3 p = 36 u
1 p = 36 u ÷ 3 = 12 u
Amount of remaining money that Abi spent on buying more pens
=
12 x 12 u
= 6 u
Number of pens that Abi bought with
12 of her remaining money
= 6 u ÷ 1 u
= 6
Total number of pens that Abi bought
= 15 + 6
= 21
Answer(s): 21