PSLE
Shiyun had a total of 112 red and silver beads. She used 28 red beads and 25% of the silver beads. After that, the ratio of the number of red beads to silver beads Shiyun had was 10 : 3.

1. What fraction of her silver beads did Shiyun use? Give your answer in the simplest form.
2. How many beads did Shiyun have in the end?

	Red beads	Silver beads	Total
Before	10 u + 28	4 u	14 u + 28
Change	- 28	- 1 u
After	10 u	3 u	13 u
Comparing red beads and silver beads in the end	10	3	13

(a)
25% = ²⁵₁₀₀ = ¹₄

Fraction of her silver beads that Shiyun used = ¹₄

(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 = 4 u
Number of red beads at first = 10 u + 28

Total number of beads at first
= 4 u + 10 u + 28
= 14 u + 28

14 u + 28 = 112
14 u = 112 - 28
14 u = 84

1 u = 84 ÷ 14 = 6

Number of silver beads in the end = 3 u
Number of red beads in the end = 10 u

Total number of beads in the end
= 10 u + 3 u
= 13 u
= 13 x 6
= 78

Answer(s): (a)¹₄; (b) 78