Natalie has a bag containing some yellow and green buttons. If she removes 10 yellow buttons, 40% of the buttons in the bag are green. If she removes another 20 green buttons, 30% of the buttons in the bag are green. How many yellow buttons are in the bag?
| |
Yellow buttons |
Green buttons |
| Before |
21 u + 10 |
14 u |
| Change 1 |
- 10 |
|
| After 1 |
3x7 =
21 u |
2x7 =
14 u |
| Change 2 |
|
- 20 |
| After 2 |
7x3 =
21 u |
3x3 =
9 u |
40% =
40100 =
2530% =
30100 =
310The number of yellow buttons remains unchanged at the second change when she removes another 20 green buttons. Make the number of yellow buttons the same at the second change. LCM of 3 and 7 is 21.
Number of green buttons removed
= 14 u - 9 u
= 5 u
5 u = 20
1 u = 20 ÷ 5 = 4
Number of yellow buttons at first
= 21 u + 10
= 21 x 4 + 10
= 84 + 10
= 94
Answer(s): 94
