There are 20% as many red balls as brown balls in Risa's collection of balls. The number of white balls is 30% fewer than the number of brown balls. There are 480 more white balls than red balls.

1. Find the total number of balls in the collection.
2. What percentage are the number of brown balls as compared to the number of white balls? Leave your answer as a mixed number in its simplest form.

Red	Brown	White
1x2	5x2
	10x1	7x1
2 u	10 u	7 u

(a)
20% = ²⁰₁₀₀ = ¹₅

100% - 30% = 70%
70% = ⁷⁰₁₀₀ = ⁷₁₀

The number of brown balls is the repeated identity. Make the number of brown balls the same.  LCM of 5 and 10 is 10.

Number of more white balls than red balls
= 7 u - 2 u
= 5 u

5 u = 480

1 u = 480 ÷ 5 = 96

Total number of balls in the collection
= 2 u + 10 u + 7 u 
= 19 u
= 19 x 96
= 1824

(b)
Percentage of the number of brown balls as compared to the number of white balls
= ¹⁰₇ x 100%
= ¹⁰⁰⁰₇ %
= 142⁶₇ %

Answer(s): (a) 1824; (b) 142⁶₇ %