There were some brown, black and gold pencils in a box.
213 of the pencils were black. The ratio of the number of brown pencils to the number of gold pencils was 4 : 7. There were 280 fewer black pencils than gold pencils.
- Find the ratio of the number of brown pencils to the number of black pencils to the number of gold pencils in the box.
- How many gold pencils were there?
Black |
Brown |
Gold |
Total |
2 |
11 |
13 |
|
4 |
7 |
|
2 u |
4 u |
7 u |
13 u |
(a)
Brown : Black : Gold
4 : 2 : 7
(b)
Number of fewer black pencils than gold pencils
= 7 u - 2 u
= 5 u
5 u = 280
1 u = 280 ÷ 5 = 56
Number of gold pencils
= 7 u
= 7 x 56
= 392
Answer(s): (a) 4 : 2 : 7; (b) 392