PSLE Lee kept his grey and black balls in two boxes. The ratio of the number of grey to black balls in the first box was 1 : 2 and it was 1 : 8 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 |
1x9 9 u |
1x9 9 u |
3x3 |
9x1 |
Grey |
Black |
Grey |
Black |
1x3 |
2x3 |
1x1 |
8x1 |
3 u |
6 u |
1 u |
8 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 3 and 9 is 9.
Total number of black balls
= 6 u + 8 u
= 14 u
Total number of balls
= 9 u + 9 u
= 18 u
Fraction of Lee's balls that were black balls
=
1418 =
79 Answer(s):
79