Jen has a bag containing some silver and gold stickers. If she adds in 18 silver stickers, 20% of the stickers in the bag are gold. If she adds in another 30 gold stickers, 30% of the stickers in the bag are gold. How many silver stickers are in the bag?
| |
Silver stickers |
Gold stickers |
| Before |
28 u - 18 |
7 u |
| Change 1 |
+ 18 |
|
| After 1 |
4x7 =
28 u |
1x7 =
7 u |
| Change 2 |
|
+ 30 |
| After 2 |
7x4 =
28 u |
3x4 =
12 u |
20% =
20100 =
1530% =
30100 =
310The number of silver stickers remains unchanged at the second change when she adds in another 30 gold stickers. Make the number of silver stickers the same at the second change. LCM of 4 and 7 is 28.
Number of gold stickers added
= 12 u - 7 u
= 5 u
5 u = 30
1 u = 30 ÷ 5 = 6
Number of silver stickers at first
= 28 u - 18
= 28 x 6 - 18
= 168 - 18
= 150
Answer(s): 150
