PSLE
Opal had a total of 210 blue and red beads. She used 20 blue beads and 75% of the red beads. After that, the ratio of the number of blue beads to red beads Opal had was 6 : 1.

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

	Blue	Red	Total
Before	6 u + 20	4 u	10 u + 20
Change	- 20	- 3 u
After	6 u	1 u	7 u
Comparing blue beads and red beads in the end	6	1	7

(a)
75% = ⁷⁵₁₀₀ = ³₄

Fraction of her red beads that Opal used = ³₄

Fraction of her red beads that Opal was left with
= 1 - ³₄
= ¹₄

(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 = 4 u
Number of blue beads at first = 6 u + 20

Total number of beads at first
= 4 u + 6 u + 20
= 10 u + 20

10 u + 20 = 210
10 u = 210 - 20
10 u = 190

1 u = 190 ÷ 10 = 19

Number of red beads in the end = 1 u
Number of blue beads in the end = 6 u

Number of more blue beads than red beads that Opal had in the end
= 6 u - 1 u
= 5 u
= 5 x 19
= 95

Answer(s): (a)¹₄; (b) 95