Tiffany spent
45 of her money on 14 pens and 6 pencils. The cost of each pencil is 3 times the cost of each pen. She bought some more pens with
78 of her remaining money. How many pens did Tiffany buy altogether?
| 14 pens + 6 pencils |
Remaining
amount |
Total
amount |
| 4 p = 32 u |
1 p = 8 u |
5 p |
14
pens |
6
pencils |
More pens |
Left |
|
| |
|
7 |
1 |
|
| 14 u |
18 u |
7 u |
|
|
Cost of 1 pen = 1 u
Cost of 1 pencil = 3 u
Cost of 14 pens = 14 x 1 u = 14 u
Cost of 6 pencils = 6 x 3 u = 18 u
Cost of 14 pens + 6 pencils
= 14 u + 18 u
= 32 u
4 p = 32 u
1 p = 32 u ÷ 4 = 8 u
Amount of remaining money that Tiffany spent on buying more pens
=
78 x 8 u
= 7 u
Number of pens that Tiffany bought with
78 of her remaining money
= 7 u ÷ 1 u
= 7
Total number of pens that Tiffany bought
= 14 + 7
= 21
Answer(s): 21
