PSLE Cindy had a total of 194 blue and silver beads. She used 26 blue beads and 20% of the silver beads. After that, the ratio of the number of blue beads to silver beads Cindy had was 9 : 4.
- What fraction of her silver beads did Cindy use? Give your answer in the simplest form.
- How many beads did Cindy have in the end?
|
Blue beads |
Silver beads |
Total |
Before |
9 u + 26 |
5 u |
14 u + 26 |
Change |
- 26 |
- 1 u |
|
After |
9 u |
4 u |
13 u |
Comparing blue beads and silver beads in the end |
9 |
4 |
13 |
(a)
20% =
20100 =
15 Fraction of her silver beads that Cindy used =
15 (b)
The number of silver 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 silver beads at first = 5 u
Number of blue beads at first = 9 u + 26
Total number of beads at first
= 5 u + 9 u + 26
= 14 u + 26
14 u + 26 = 194
14 u = 194 - 26
14 u = 168
1 u = 168 ÷ 14 = 12
Number of silver beads in the end = 4 u
Number of blue beads in the end = 9 u
Total number of beads in the end
= 9 u + 4 u
= 13 u
= 13 x 12
= 156
Answer(s): (a)
15; (b) 156