Daniel has a total of 62 of silver and red notebooks.
15 of the silver notebooks and half of the red notebooks are new. How many of his red notebooks are new if he has a total of 19 new notebooks?
| |
Silver notebooks |
Red notebooks |
Total |
| Total |
5 u |
2 p |
62 |
| New |
1 u |
1 p |
19 |
| Old |
4 u |
1 p |
43 |
Number of old notebooks
= 62 - 19
= 43
1 u + 1 p = 19 --- (1)
4 u + 1 p = 43 --- (2)
(2) - (1)
(4 u + 1 p) - (1 u + 1 p) = 43 - 19
4 u - 1 u = 24
3 u = 24
1 u = 24 ÷ 3 = 8
Number of new red notebooks
= 19 - 1 u
= 19 - 8
= 11
Answer(s): 11
