Charlie has a total of 54 of red and pink notebooks.
15 of the red notebooks and half of the pink notebooks are new. How many of his pink notebooks are new if he has a total of 12 new notebooks?
| |
Red notebooks |
Pink notebooks |
Total |
| Total |
5 u |
2 p |
54 |
| New |
1 u |
1 p |
12 |
| Old |
4 u |
1 p |
42 |
Number of old notebooks
= 54 - 12
= 42
1 u + 1 p = 12 --- (1)
4 u + 1 p = 42 --- (2)
(2) - (1)
(4 u + 1 p) - (1 u + 1 p) = 42 - 12
4 u - 1 u = 30
3 u = 30
1 u = 30 ÷ 3 = 10
Number of new pink notebooks
= 12 - 1 u
= 12 - 10
= 2
Answer(s): 2
