Elijah has a total of 25 of silver and black markers.
15 of the silver markers and half of the black markers are new. How many of his black markers are new if he has a total of 8 new markers?
| |
Silver markers |
Black markers |
Total |
| Total |
5 u |
2 p |
25 |
| New |
1 u |
1 p |
8 |
| Old |
4 u |
1 p |
17 |
Number of old markers
= 25 - 8
= 17
1 u + 1 p = 8 --- (1)
4 u + 1 p = 17 --- (2)
(2) - (1)
(4 u + 1 p) - (1 u + 1 p) = 17 - 8
4 u - 1 u = 9
3 u = 9
1 u = 9 ÷ 3 = 3
Number of new black markers
= 8 - 1 u
= 8 - 3
= 5
Answer(s): 5
