The number of either yellow or black shirts is equal to= 525. Now, from the condition, you have these two equations B + Y = 525, (1) (where B = #of black shirts; Y = #of yellow shirts) B - Y = 85 (2) Add these two equations to get 2B = 525 + 85 = 610 ====> B = 610/2 = 305. Then from eq(1), Y = 525 - 305 = 220. Answer. 305 black shirts and 220 yellow shirts.
As number of black is 305, number of black and green =