Brandon has a total of 84 of silver and brown pencils.
16 of the silver pencils and half of the brown pencils are new. How many of his brown pencils are new if he has a total of 20 new pencils?
|
Silver pencils |
Brown pencils |
Total |
Total |
6 u |
2 p |
84 |
New |
1 u |
1 p |
20 |
Old |
5 u |
1 p |
64 |
Number of old pencils
= 84 - 20
= 64
1 u + 1 p = 20 --- (1)
5 u + 1 p = 64 --- (2)
(2) - (1)
(5 u + 1 p) - (1 u + 1 p) = 64 - 20
5 u - 1 u = 44
4 u = 44
1 u = 44 ÷ 4 = 11
Number of new brown pencils
= 20 - 1 u
= 20 - 11
= 9
Answer(s): 9