Tim has a total of 69 of black and pink markers.
15 of the black markers and half of the pink markers are new. How many of his pink markers are new if he has a total of 21 new markers?
|
Black markers |
Pink markers |
Total |
Total |
5 u |
2 p |
69 |
New |
1 u |
1 p |
21 |
Old |
4 u |
1 p |
48 |
Number of old markers
= 69 - 21
= 48
1 u + 1 p = 21 --- (1)
4 u + 1 p = 48 --- (2)
(2) - (1)
(4 u + 1 p) - (1 u + 1 p) = 48 - 21
4 u - 1 u = 27
3 u = 27
1 u = 27 ÷ 3 = 9
Number of new pink markers
= 21 - 1 u
= 21 - 9
= 12
Answer(s): 12