PSLE
Risa had a total of 125 yellow and green beads. She used 13 yellow beads and 80% of the green beads. After that, the ratio of the number of yellow beads to green beads Risa had was 9 : 1.

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

	Yellow	Green	Total
Before	9 u + 13	5 u	14 u + 13
Change	- 13	- 4 u
After	9 u	1 u	10 u
Comparing yellow beads and green beads in the end	9	1	10

(a)
80% = ⁸⁰₁₀₀ = ⁴₅

Fraction of her green beads that Risa used = ⁴₅

Fraction of her green beads that Risa was left with
= 1 - ⁴₅
= ¹₅

(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 = 5 u
Number of yellow beads at first = 9 u + 13

Total number of beads at first
= 5 u + 9 u + 13
= 14 u + 13

14 u + 13 = 125
14 u = 125 - 13
14 u = 112

1 u = 112 ÷ 14 = 8

Number of green beads in the end = 1 u
Number of yellow beads in the end = 9 u

Number of more yellow beads than green beads that Risa had in the end
= 9 u - 1 u
= 8 u
= 8 x 8
= 64

Answer(s): (a)¹₅; (b) 64