Peter has a total of 26 of white and blue notebooks.
13 of the white notebooks and half of the blue notebooks are new. How many of his blue notebooks are new if he has a total of 11 new notebooks?
| |
White notebooks |
Blue notebooks |
Total |
| Total |
3 u |
2 p |
26 |
| New |
1 u |
1 p |
11 |
| Old |
2 u |
1 p |
15 |
Number of old notebooks
= 26 - 11
= 15
1 u + 1 p = 11 --- (1)
2 u + 1 p = 15 --- (2)
(2) - (1)
(2 u + 1 p) - (1 u + 1 p) = 15 - 11
2 u - 1 u = 4
1 u = 4
1 u = 4 ÷ 1 = 4
Number of new blue notebooks
= 11 - 1 u
= 11 - 4
= 7
Answer(s): 7
