Xylia has a bag containing some red and yellow stickers. If she adds in 15 red stickers, 30% of the stickers in the bag are yellow. If she adds in another 28 yellow stickers, 50% of the stickers in the bag are yellow. How many red stickers are in the bag?
| |
Red stickers |
Yellow stickers |
| Before |
7 u - 15 |
3 u |
| Change 1 |
+ 15 |
|
| After 1 |
7x1 =
7 u |
3x1 =
3 u |
| Change 2 |
|
+ 28 |
| After 2 |
1x7 =
7 u |
1x7 =
7 u |
30% =
30100 =
31050% =
50100 =
12The number of red stickers remains unchanged at the second change when she adds in another 28 yellow stickers. Make the number of red stickers the same at the second change. LCM of 7 and 1 is 7.
Number of yellow stickers added
= 7 u - 3 u
= 4 u
4 u = 28
1 u = 28 ÷ 4 = 7
Number of red stickers at first
= 7 u - 15
= 7 x 7 - 15
= 49 - 15
= 34
Answer(s): 34
