PSLE
Xuan had a total of 75 red and silver beads. She used 25 red beads and 60% of the silver beads. After that, the ratio of the number of red beads to silver beads Xuan had was 5 : 2.

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

	Red beads	Silver beads	Total
Before	5 u + 25	5 u	10 u + 25
Change	- 25	- 3 u
After	5 u	2 u	7 u
Comparing red beads and silver beads in the end	5	2	7

(a)
60% = ⁶⁰₁₀₀ = ³₅

Fraction of her silver beads that Xuan used = ³₅

(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 red beads at first = 5 u + 25

Total number of beads at first
= 5 u + 5 u + 25
= 10 u + 25

10 u + 25 = 75
10 u = 75 - 25
10 u = 50

1 u = 50 ÷ 10 = 5

Number of silver beads in the end = 2 u
Number of red beads in the end = 5 u

Total number of beads in the end
= 5 u + 2 u
= 7 u
= 7 x 5
= 35

Answer(s): (a)³₅; (b) 35