Caden has a total of 50 of grey and purple pencils.
16 of the grey pencils and half of the purple pencils are new. How many of his purple pencils are new if he has a total of 13 new pencils?
| |
Grey pencils |
Purple pencils |
Total |
| Total |
6 u |
2 p |
50 |
| New |
1 u |
1 p |
13 |
| Old |
5 u |
1 p |
37 |
Number of old pencils
= 50 - 13
= 37
1 u + 1 p = 13 --- (1)
5 u + 1 p = 37 --- (2)
(2) - (1)
(5 u + 1 p) - (1 u + 1 p) = 37 - 13
5 u - 1 u = 24
4 u = 24
1 u = 24 ÷ 4 = 6
Number of new purple pencils
= 13 - 1 u
= 13 - 6
= 7
Answer(s): 7
