Gwen has a bag containing some blue and yellow pens. If she removes 11 blue pens, 25% of the pens in the bag are yellow. If she adds another 22 yellow pens, 50% of the pens in the bag are yellow. How many blue pens are in the bag?
| |
Blue pens |
Yellow pens |
| Before |
3 u + 11 |
1 u |
| Change 1 |
- 11 |
|
| After 1 |
3x1 =
3 u |
1x1 =
1 u |
| Change 2 |
|
+ 22 |
| After 2 |
1x3 =
3 u |
1x3 =
3 u |
25% =
25100 =
1450% =
50100 =
12The number of blue pens remains unchanged at the second change when she adds another 22 yellow pens. Make the number of blue pens the same at the second change. LCM of 3 and 1 is 3.
Number of yellow pens added
= 3 u - 1 u
= 2 u
2 u = 22
1 u = 22 ÷ 2 = 11
Number of blue pens at first
= 3 u + 11
= 3 x 11 + 11
= 33 + 11
= 44
Answer(s): 44
