There were some grey, brown and black notebooks in a box.
211 of the notebooks were brown. The ratio of the number of grey notebooks to the number of black notebooks was 4 : 5. There were 282 fewer brown notebooks than black notebooks.
- Find the ratio of the number of grey notebooks to the number of brown notebooks to the number of black notebooks in the box.
- How many black notebooks were there?
Brown |
Grey |
Black |
Total |
2 |
9 |
11 |
|
4 |
5 |
|
2 u |
4 u |
5 u |
11 u |
(a)
Grey : Brown : Black
4 : 2 : 5
(b)
Number of fewer brown notebooks than black notebooks
= 5 u - 2 u
= 3 u
3 u = 282
1 u = 282 ÷ 3 = 94
Number of black notebooks
= 5 u
= 5 x 94
= 470
Answer(s): (a) 4 : 2 : 5; (b) 470