PSLE
Risa had a total of 208 orange and green beads. She used 40 orange beads and 40% of the green beads. After that, the ratio of the number of orange beads to green beads Risa had was 7 : 3.

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

	Orange beads	Green beads	Total
Before	7 u + 40	5 u	12 u + 40
Change	- 40	- 2 u
After	7 u	3 u	10 u
Comparing orange beads and green beads in the end	7	3	10

(a)
40% = ⁴⁰₁₀₀ = ²₅

Fraction of her green beads that Risa used = ²₅

(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 orange beads at first = 7 u + 40

Total number of beads at first
= 5 u + 7 u + 40
= 12 u + 40

12 u + 40 = 208
12 u = 208 - 40
12 u = 168

1 u = 168 ÷ 12 = 14

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

Total number of beads in the end
= 7 u + 3 u
= 10 u
= 10 x 14
= 140

Answer(s): (a)²₅; (b) 140