PSLE
Sarah had a total of 198 yellow and green beads. She used 22 yellow beads and 90% of the green beads. After that, the ratio of the number of yellow beads to green beads Sarah had was 6 : 1.

1. What fraction of her green beads was Sarah left with? Give your answer in the simplest form.
2. How many more yellow beads than green beads did Sarah have in the end?

	Yellow	Green	Total
Before	6 u + 22	10 u	16 u + 22
Change	- 22	- 9 u
After	6 u	1 u	7 u
Comparing yellow beads and green beads in the end	6	1	7

(a)
90% = ⁹⁰₁₀₀ = ⁹₁₀

Fraction of her green beads that Sarah used = ⁹₁₀

Fraction of her green beads that Sarah was left with
= 1 - ⁹₁₀
= ¹₁₀

(b)
The number of green 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 green beads at first = 10 u
Number of yellow beads at first = 6 u + 22

Total number of beads at first
= 10 u + 6 u + 22
= 16 u + 22

16 u + 22 = 198
16 u = 198 - 22
16 u = 176

1 u = 176 ÷ 16 = 11

Number of green beads in the end = 1 u
Number of yellow beads in the end = 6 u

Number of more yellow beads than green beads that Sarah had in the end
= 6 u - 1 u
= 5 u
= 5 x 11
= 55

Answer(s): (a)¹₁₀; (b) 55