PSLE
Erika had a total of 161 red and orange beads. She used 17 red beads and 80% of the orange beads. After that, the ratio of the number of red beads to orange beads Erika had was 4 : 1.

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

	Red	Orange	Total
Before	4 u + 17	5 u	9 u + 17
Change	- 17	- 4 u
After	4 u	1 u	5 u
Comparing red beads and orange beads in the end	4	1	5

(a)
80% = ⁸⁰₁₀₀ = ⁴₅

Fraction of her orange beads that Erika used = ⁴₅

Fraction of her orange beads that Erika was left with
= 1 - ⁴₅
= ¹₅

(b)
The number of orange 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 orange beads at first = 5 u
Number of red beads at first = 4 u + 17

Total number of beads at first
= 5 u + 4 u + 17
= 9 u + 17

9 u + 17 = 161
9 u = 161 - 17
9 u = 144

1 u = 144 ÷ 9 = 16

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

Number of more red beads than orange beads that Erika had in the end
= 4 u - 1 u
= 3 u
= 3 x 16
= 48

Answer(s): (a)¹₅; (b) 48