In a boutique that sells skirts, 440 blue skirts were sold and 10% of the remaining skirts that were sold were silver. Of the leftover, 60% of the skirts sold were black skirts and the rest were red skirts. Given that the number of red skirts sold was 20% of the total number of skirts sold, how many silver and blue skirts were sold altogether?
10% = ¹⁰₁₀₀ = ¹₁₀
60% = ⁶⁰₁₀₀ = ³₅
20% = ²⁰₁₀₀ = ¹₅

Blue	Silver	Black	Red
440	1x5	9x5
		3x9	2x9
4x18			1x18
40 u	5 u	27 u	18 u

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

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

Number of blue skirts
= 72 u - 5 u - 27 u
= 40 u

40 u = 440

1 u = 440 ÷ 40 = 11

Number of silver and blue skirts
= 5 u + 440
= (5 x 11) + 440
= 55 + 440
= 495

Answer(s): 495