There are 15% as many yellow marbles as grey marbles in Jaslyn's collection of marbles. The number of red marbles is 40% fewer than the number of grey marbles. There are 504 more red marbles than yellow marbles.

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

Yellow	Grey	Red
3x1	20x1
	5x4	3x4
3 u	20 u	12 u

(a)
15% = ¹⁵₁₀₀ = ³₂₀

100% - 40% = 60%
60% = ⁶⁰₁₀₀ = ³₅

The number of grey marbles is the repeated identity. Make the number of grey marbles the same.  LCM of 20 and 5 is 20.

Number of more red marbles than yellow marbles
= 12 u - 3 u
= 9 u

9 u = 504

1 u = 504 ÷ 9 = 56

Total number of marbles in the collection
= 3 u + 20 u + 12 u 
= 35 u
= 35 x 56
= 1960

(b)
Percentage of the number of grey marbles as compared to the number of red marbles
= ⁵₃ x 100%
= ⁵⁰⁰₃ %
= 166²₃ %

Answer(s): (a) 1960; (b) 166²₃ %