PSLE At first, Gwen had an equal number of black and red marbles . She gave away
35 of her black marbles and some red marbles. In the end, she was left with
25 of her marbles. What fraction of the red marbles did Gwen give away?
|
Black |
Red |
Total |
Comparing black marbles and red marbles at first |
1x5x1 = 5 u |
1x5x1 = 5 u |
2x5x1 = 10 u |
Before |
5x1 = 5 u |
5 u |
5x2 = 10 u |
Change |
- 3x1 = - 3 u |
- 3 u |
- 2x2 = - 6 u |
After |
2x1 = 2 u |
2 u |
3x2 = 4 u |
After
2x1 =
2 u2 u
3x2 =
4 uThe number of black marbles at first is repeated. Make the number of black marbles the first the same. LCM of 5 and 1 is 5.
The total number of marbles at first is repeated. Make the total number of marbles at first the same. LCM of 10 and 5 is 10.
Number of red marbles that Gwen was left with
= 4 u - 2 u
= 2 u
Number of red marbles that Gwen gave away
= 5 u - 2 u
= 3 u
Fraction of the red marbles that Gwen gave away =
35 Answer(s):
35