PSLE
Anna had a total of 181 green and red beads. She used 11 green beads and 10% of the red beads. After that, the ratio of the number of green beads to red beads Anna had was 7 : 9.

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

	Green beads	Red beads	Total
Before	7 u + 11	10 u	17 u + 11
Change	- 11	- 1 u
After	7 u	9 u	16 u
Comparing green beads and red beads in the end	7	9	16

(a)
10% = ¹⁰₁₀₀ = ¹₁₀

Fraction of her red beads that Anna used = ¹₁₀

(b)
The number of red 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 red beads at first = 10 u
Number of green beads at first = 7 u + 11

Total number of beads at first
= 10 u + 7 u + 11
= 17 u + 11

17 u + 11 = 181
17 u = 181 - 11
17 u = 170

1 u = 170 ÷ 17 = 10

Number of red beads in the end = 9 u
Number of green beads in the end = 7 u

Total number of beads in the end
= 7 u + 9 u
= 16 u
= 16 x 10
= 160

Answer(s): (a)¹₁₀; (b) 160