PSLE
Lynn had a total of 159 orange and red beads. She used 40 orange beads and 70% of the red beads. After that, the ratio of the number of orange beads to red beads Lynn had was 7 : 3.

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

	Orange	Red	Total
Before	7 u + 40	10 u	17 u + 40
Change	- 40	- 7 u
After	7 u	3 u	10 u
Comparing orange beads and red beads in the end	7	3	10

(a)
70% = ⁷⁰₁₀₀ = ⁷₁₀

Fraction of her red beads that Lynn used = ⁷₁₀

Fraction of her red beads that Lynn was left with
= 1 - ⁷₁₀
= ³₁₀

(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 orange beads at first = 7 u + 40

Total number of beads at first
= 10 u + 7 u + 40
= 17 u + 40

17 u + 40 = 159
17 u = 159 - 40
17 u = 119

1 u = 119 ÷ 17 = 7

Number of red beads in the end = 3 u
Number of orange beads in the end = 7 u

Number of more orange beads than red beads that Lynn had in the end
= 7 u - 3 u
= 4 u
= 4 x 7
= 28

Answer(s): (a)³₁₀; (b) 28