Irene has a bag containing some blue and yellow buttons. If she removes 17 blue buttons, 20% of the buttons in the bag are yellow. If she removes another 50 yellow buttons, 10% of the buttons in the bag are yellow. How many blue buttons are in the bag?
| |
Blue buttons |
Yellow buttons |
| Before |
36 u + 17 |
9 u |
| Change 1 |
- 17 |
|
| After 1 |
4x9 =
36 u |
1x9 =
9 u |
| Change 2 |
|
- 50 |
| After 2 |
9x4 =
36 u |
1x4 =
4 u |
20% =
20100 =
1510% =
10100 =
110The number of blue buttons remains unchanged at the second change when she removes another 50 yellow buttons. Make the number of blue buttons the same at the second change. LCM of 4 and 9 is 36.
Number of yellow buttons removed
= 9 u - 4 u
= 5 u
5 u = 50
1 u = 50 ÷ 5 = 10
Number of blue buttons at first
= 36 u + 17
= 36 x 10 + 17
= 360 + 17
= 377
Answer(s): 377
