Michael has a total of 52 of blue and yellow pencils.
16 of the blue pencils and half of the yellow pencils are new. How many of his yellow pencils are new if he has a total of 12 new pencils?
| |
Blue pencils |
Yellow pencils |
Total |
| Total |
6 u |
2 p |
52 |
| New |
1 u |
1 p |
12 |
| Old |
5 u |
1 p |
40 |
Number of old pencils
= 52 - 12
= 40
1 u + 1 p = 12 --- (1)
5 u + 1 p = 40 --- (2)
(2) - (1)
(5 u + 1 p) - (1 u + 1 p) = 40 - 12
5 u - 1 u = 28
4 u = 28
1 u = 28 ÷ 4 = 7
Number of new yellow pencils
= 12 - 1 u
= 12 - 7
= 5
Answer(s): 5
