There were some brown, black and gold pens in a box.
110 of the pens were black. The ratio of the number of brown pens to the number of gold pens was 4 : 5. There were 280 fewer black pens than gold pens.
- Find the ratio of the number of brown pens to the number of black pens to the number of gold pens in the box.
- How many gold pens were there?
Black |
Brown |
Gold |
Total |
1 |
9 |
10 |
|
4 |
5 |
|
1 u |
4 u |
5 u |
10 u |
(a)
Brown : Black : Gold
4 : 1 : 5
(b)
Number of fewer black pens than gold pens
= 5 u - 1 u
= 4 u
4 u = 280
1 u = 280 ÷ 4 = 70
Number of gold pens
= 5 u
= 5 x 70
= 350
Answer(s): (a) 4 : 1 : 5; (b) 350