There are 20% as many gold balls as silver balls in Eva's collection of balls. The number of grey balls is 30% fewer than the number of silver balls. There are 415 more grey balls than gold balls.

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

Gold	Silver	Grey
1x2	5x2
	10x1	7x1
2 u	10 u	7 u

(a)
20% = ²⁰₁₀₀ = ¹₅

100% - 30% = 70%
70% = ⁷⁰₁₀₀ = ⁷₁₀

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

Number of more grey balls than gold balls
= 7 u - 2 u
= 5 u

5 u = 415

1 u = 415 ÷ 5 = 83

Total number of balls in the collection
= 2 u + 10 u + 7 u 
= 19 u
= 19 x 83
= 1577

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

Answer(s): (a) 1577; (b) 142⁶₇ %