George has a total of 45 of yellow and white files.
13 of the yellow files and half of the white files are new. How many of his white files are new if he has a total of 19 new files?
| |
Yellow files |
White files |
Total |
| Total |
3 u |
2 p |
45 |
| New |
1 u |
1 p |
19 |
| Old |
2 u |
1 p |
26 |
Number of old files
= 45 - 19
= 26
1 u + 1 p = 19 --- (1)
2 u + 1 p = 26 --- (2)
(2) - (1)
(2 u + 1 p) - (1 u + 1 p) = 26 - 19
2 u - 1 u = 7
1 u = 7
1 u = 7 ÷ 1 = 7
Number of new white files
= 19 - 1 u
= 19 - 7
= 12
Answer(s): 12
