There were some black, gold and silver files in a box.
110 of the files were gold. The ratio of the number of black files to the number of silver files was 4 : 5. There were 312 fewer gold files than silver files.
- Find the ratio of the number of black files to the number of gold files to the number of silver files in the box.
- How many silver files were there?
Gold |
Black |
Silver |
Total |
1 |
9 |
10 |
|
4 |
5 |
|
1 u |
4 u |
5 u |
10 u |
(a)
Black : Gold : Silver
4 : 1 : 5
(b)
Number of fewer gold files than silver files
= 5 u - 1 u
= 4 u
4 u = 312
1 u = 312 ÷ 4 = 78
Number of silver files
= 5 u
= 5 x 78
= 390
Answer(s): (a) 4 : 1 : 5; (b) 390