PSLE
Jean had a total of 82 blue and red beads. She used 28 blue beads and 80% of the red beads. After that, the ratio of the number of blue beads to red beads Jean had was 4 : 1.

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

	Blue beads	Red beads	Total
Before	4 u + 28	5 u	9 u + 28
Change	- 28	- 4 u
After	4 u	1 u	5 u
Comparing blue beads and red beads in the end	4	1	5

(a)
80% = ⁸⁰₁₀₀ = ⁴₅

Fraction of her red beads that Jean used = ⁴₅

(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 blue beads at first = 4 u + 28

Total number of beads at first
= 5 u + 4 u + 28
= 9 u + 28

9 u + 28 = 82
9 u = 82 - 28
9 u = 54

1 u = 54 ÷ 9 = 6

Number of red beads in the end = 1 u
Number of blue beads in the end = 4 u

Total number of beads in the end
= 4 u + 1 u
= 5 u
= 5 x 6
= 30

Answer(s): (a)⁴₅; (b) 30