PSLE Tom kept his brown and black stars in two boxes. The ratio of the number of brown to black stars in the first box was 5 : 7 and it was 1 : 3 in the second box. The two boxes contained the same number of stars. What fraction of Tom's stars were brown stars?
First box |
Second box |
1x12 12 u |
1x12 12 u |
12x1 |
4x3 |
Brown |
Black |
Brown |
Black |
5x1 |
7x1 |
1x3 |
3x3 |
5 u |
7 u |
3 u |
9 u |
The total number of stars in the first box and the second box is the same. Make the total number of stars in each box the same. LCM of 12 and 4 is 12.
Total number of brown stars
= 5 u + 3 u
= 8 u
Total number of stars
= 12 u + 12 u
= 24 u
Fraction of Tom's stars that were brown stars
=
824 =
13 Answer(s):
13