Warren has a total of 46 of gold and silver pencils.
16 of the gold pencils and half of the silver pencils are new. How many of his silver pencils are new if he has a total of 15 new pencils?
| |
Gold pencils |
Silver pencils |
Total |
| Total |
6 u |
2 p |
46 |
| New |
1 u |
1 p |
15 |
| Old |
5 u |
1 p |
31 |
Number of old pencils
= 46 - 15
= 31
1 u + 1 p = 15 --- (1)
5 u + 1 p = 31 --- (2)
(2) - (1)
(5 u + 1 p) - (1 u + 1 p) = 31 - 15
5 u - 1 u = 16
4 u = 16
1 u = 16 ÷ 4 = 4
Number of new silver pencils
= 15 - 1 u
= 15 - 4
= 11
Answer(s): 11
