Ian has a total of 48 of silver and grey markers.
14 of the silver markers and half of the grey markers are new. How many of his grey markers are new if he has a total of 15 new markers?
|
Silver markers |
Grey markers |
Total |
Total |
4 u |
2 p |
48 |
New |
1 u |
1 p |
15 |
Old |
3 u |
1 p |
33 |
Number of old markers
= 48 - 15
= 33
1 u + 1 p = 15 --- (1)
3 u + 1 p = 33 --- (2)
(2) - (1)
(3 u + 1 p) - (1 u + 1 p) = 33 - 15
3 u - 1 u = 18
2 u = 18
1 u = 18 ÷ 2 = 9
Number of new grey markers
= 15 - 1 u
= 15 - 9
= 6
Answer(s): 6