Nora had 128 crayons.
34 of them were brown crayons and the rest were grey crayons. After she had given away some brown crayons, the ratio of the number of brown crayons to the number of grey crayons became 3 : 4. How many brown crayons did she give away?
| |
Brown |
Grey |
Total |
| Before |
3x4 =
12 u |
1x4 =
4 u |
4x4 =
16 u |
| Change |
- 9 u |
|
|
| After |
3 u |
4 u |
7 u |
The number of grey crayons remained unchanged.
LCM of 1 and 4 = 4
Total number of crayons at first = 16 u
16 u = 128
1 u = 128 ÷ 16 = 8
Number of brown crayons that she gave away
= 12 u - 3 u
= 9 u
= 9 x 8
= 72
Answer(s):72
