Ken has a total of 33 of white and red markers.
13 of the white markers and half of the red markers are new. How many of his red markers are new if he has a total of 12 new markers?
| |
White markers |
Red markers |
Total |
| Total |
3 u |
2 p |
33 |
| New |
1 u |
1 p |
12 |
| Old |
2 u |
1 p |
21 |
Number of old markers
= 33 - 12
= 21
1 u + 1 p = 12 --- (1)
2 u + 1 p = 21 --- (2)
(2) - (1)
(2 u + 1 p) - (1 u + 1 p) = 21 - 12
2 u - 1 u = 9
1 u = 9
1 u = 9 ÷ 1 = 9
Number of new red markers
= 12 - 1 u
= 12 - 9
= 3
Answer(s): 3
