PSLE
Marion had a total of 180 green and silver beads. She used 15 green beads and 80% of the silver beads. After that, the ratio of the number of green beads to silver beads Marion had was 10 : 1.

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

	Green beads	Silver beads	Total
Before	10 u + 15	5 u	15 u + 15
Change	- 15	- 4 u
After	10 u	1 u	11 u
Comparing green beads and silver beads in the end	10	1	11

(a)
80% = ⁸⁰₁₀₀ = ⁴₅

Fraction of her silver beads that Marion used = ⁴₅

(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 green beads at first = 10 u + 15

Total number of beads at first
= 5 u + 10 u + 15
= 15 u + 15

15 u + 15 = 180
15 u = 180 - 15
15 u = 165

1 u = 165 ÷ 15 = 11

Number of silver beads in the end = 1 u
Number of green beads in the end = 10 u

Total number of beads in the end
= 10 u + 1 u
= 11 u
= 11 x 11
= 121

Answer(s): (a)⁴₅; (b) 121