In a shopping centre that sells windbreakers, 1000 gold windbreakers were sold and 10% of the remaining windbreakers that were sold were grey. Of the leftover, 60% of the windbreakers sold were black windbreakers and the rest were purple windbreakers. Given that the number of purple windbreakers sold was 20% of the total number of windbreakers sold, how many grey and gold windbreakers were sold altogether?
10% = ¹⁰₁₀₀ = ¹₁₀
60% = ⁶⁰₁₀₀ = ³₅
20% = ²⁰₁₀₀ = ¹₅

Gold	Grey	Black	Purple
1000	1x5	9x5
		3x9	2x9
4x18			1x18
40 u	5 u	27 u	18 u

The total number of black and purple shirts is the combined repeated identity. Make the total number of black and purple shirts the same. LCM of 9 and 5 is 45.

The number of purple shirts is repeated. Make the number of purple shirts the same. LCM of 18 and 1 is 18.

Number of gold windbreakers
= 72 u - 5 u - 27 u
= 40 u

40 u = 1000

1 u = 1000 ÷ 40 = 25

Number of grey and gold windbreakers
= 5 u + 1000
= (5 x 25) + 1000
= 125 + 1000
= 1125

Answer(s): 1125