PSLE At first, Mary had an equal number of red and black marbles . She gave away
23 of her red marbles and some black marbles. In the end, she was left with
35 of her marbles. What fraction of the black marbles was Mary left with?
|
Red |
Black |
Total |
Comparing red marbles and black marbles at first |
1x3x5 = 15 u |
1x3x5 = 15 u |
2x3x5 = 30 u |
Before |
3x5 = 15 u |
15 u |
5x6 = 30 u |
Change |
- 2x5 = - 10 u |
- 2 u |
- 3x6 = - 12 u |
After |
1x5 = 5 u |
13 u |
2x6 = 18 u |
The number of red marbles at first is repeated. Make the number of red marbles the first the same. LCM of 3 and 1 is 3.
The total number of marbles at first is repeated. Make the total number of marbles at first the same. LCM of 6 and 5 is 30.
Number of black marbles that Mary was left with
= 18 u - 5 u
= 13 u
Fraction of the black marbles that Mary was left with =
1315 Answer(s):
1315