PSLE Lee kept his brown and black balls in two boxes. The ratio of the number of brown to black balls in the first box was 1 : 4 and it was 1 : 2 in the second box. The two boxes contained the same number of balls. What fraction of Lee's balls were black balls?
First box |
Second box |
1x15 15 u |
1x15 15 u |
5x3 |
3x5 |
Brown |
Black |
Brown |
Black |
1x3 |
4x3 |
1x5 |
2x5 |
3 u |
12 u |
5 u |
10 u |
The total number of balls in the first box and the second box is the same. Make the total number of balls in each box the same.
LCM of 5 and 3 is 15.
Total number of black balls
= 12 u + 10 u
= 22 u
Total number of balls
= 15 u + 15 u
= 30 u
Fraction of Lee's balls that were black balls
=
2230 =
1115 Answer(s):
1115