Billy has a total of 53 of blue and pink notebooks.
15 of the blue notebooks and half of the pink notebooks are new. How many of his pink notebooks are new if he has a total of 13 new notebooks?
| |
Blue notebooks |
Pink notebooks |
Total |
| Total |
5 u |
2 p |
53 |
| New |
1 u |
1 p |
13 |
| Old |
4 u |
1 p |
40 |
Number of old notebooks
= 53 - 13
= 40
1 u + 1 p = 13 --- (1)
4 u + 1 p = 40 --- (2)
(2) - (1)
(4 u + 1 p) - (1 u + 1 p) = 40 - 13
4 u - 1 u = 27
3 u = 27
1 u = 27 ÷ 3 = 9
Number of new pink notebooks
= 13 - 1 u
= 13 - 9
= 4
Answer(s): 4
