There are 20% as many white balls as grey balls in Victoria's collection of balls. The number of blue balls is 30% fewer than the number of grey balls. There are 280 more blue balls than white balls.

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

White	Grey	Blue
1x2	5x2
	10x1	7x1
2 u	10 u	7 u

(a)
20% = ²⁰₁₀₀ = ¹₅

100% - 30% = 70%
70% = ⁷⁰₁₀₀ = ⁷₁₀

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

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

5 u = 280

1 u = 280 ÷ 5 = 56

Total number of balls in the collection
= 2 u + 10 u + 7 u 
= 19 u
= 19 x 56
= 1064

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

Answer(s): (a) 1064; (b) 142⁶₇ %