Dylan has a total of 23 of blue and silver pens.
13 of the blue pens and half of the silver pens are new. How many of his silver pens are new if he has a total of 9 new pens?
| |
Blue pens |
Silver pens |
Total |
| Total |
3 u |
2 p |
23 |
| New |
1 u |
1 p |
9 |
| Old |
2 u |
1 p |
14 |
Number of old pens
= 23 - 9
= 14
1 u + 1 p = 9 --- (1)
2 u + 1 p = 14 --- (2)
(2) - (1)
(2 u + 1 p) - (1 u + 1 p) = 14 - 9
2 u - 1 u = 5
1 u = 5
1 u = 5 ÷ 1 = 5
Number of new silver pens
= 9 - 1 u
= 9 - 5
= 4
Answer(s): 4
