PSLE
Min had a total of 186 yellow and blue beads. She used 30 yellow beads and 75% of the blue beads. After that, the ratio of the number of yellow beads to blue beads Min had was 9 : 1.

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

	Yellow beads	Blue beads	Total
Before	9 u + 30	4 u	13 u + 30
Change	- 30	- 3 u
After	9 u	1 u	10 u
Comparing yellow beads and blue beads in the end	9	1	10

(a)
75% = ⁷⁵₁₀₀ = ³₄

Fraction of her blue beads that Min used = ³₄

(b)
The number of blue 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 blue beads at first = 4 u
Number of yellow beads at first = 9 u + 30

Total number of beads at first
= 4 u + 9 u + 30
= 13 u + 30

13 u + 30 = 186
13 u = 186 - 30
13 u = 156

1 u = 156 ÷ 13 = 12

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

Total number of beads in the end
= 9 u + 1 u
= 10 u
= 10 x 12
= 120

Answer(s): (a)³₄; (b) 120