PSLE Raeann had a total of 125 orange and yellow beads. She used 15 orange beads and 50% of the yellow beads. After that, the ratio of the number of orange beads to yellow beads Raeann had was 9 : 1.
- What fraction of her yellow beads did Raeann use? Give your answer in the simplest form.
- How many beads did Raeann have in the end?
|
Orange beads |
Yellow beads |
Total |
Before |
9 u + 15 |
2 u |
11 u + 15 |
Change |
- 15 |
- 1 u |
|
After |
9 u |
1 u |
10 u |
Comparing orange beads and yellow beads in the end |
9 |
1 |
10 |
(a)
50% =
50100 =
12 Fraction of her yellow beads that Raeann used =
12 (b)
The number of yellow beads in the end is repeated.
Since the numbers are already the same, we do not need to use LCM to make them the same.
Number of yellow beads at first = 2 u
Number of orange beads at first = 9 u + 15
Total number of beads at first
= 2 u + 9 u + 15
= 11 u + 15
11 u + 15 = 125
11 u = 125 - 15
11 u = 110
1 u = 110 ÷ 11 = 10
Number of yellow beads in the end = 1 u
Number of orange beads in the end = 9 u
Total number of beads in the end
= 9 u + 1 u
= 10 u
= 10 x 10
= 100
Answer(s): (a)
12; (b) 100