PSLE
Lucy had a total of 225 green and red beads. She used 30 green beads and 40% of the red beads. After that, the ratio of the number of green beads to red beads Lucy had was 10 : 3.

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

	Green beads	Red beads	Total
Before	10 u + 30	5 u	15 u + 30
Change	- 30	- 2 u
After	10 u	3 u	13 u
Comparing green beads and red beads in the end	10	3	13

(a)
40% = ⁴⁰₁₀₀ = ²₅

Fraction of her red beads that Lucy used = ²₅

(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 = 5 u
Number of green beads at first = 10 u + 30

Total number of beads at first
= 5 u + 10 u + 30
= 15 u + 30

15 u + 30 = 225
15 u = 225 - 30
15 u = 195

1 u = 195 ÷ 15 = 13

Number of red beads in the end = 3 u
Number of green beads in the end = 10 u

Total number of beads in the end
= 10 u + 3 u
= 13 u
= 13 x 13
= 169

Answer(s): (a)²₅; (b) 169