White=3(x); red=5(x); yellow=8(x); blue=4(x)... Find x in the equation " 3(x)+5(x)+8(x)+4(x)=2000".. Solving this, 20(x)=2000... x=100.. Then substitute to each equation of shirt... White=3(100)=300...red=5(100)=500... Yellow=8(100)=800...blue=4(100)=400. Therefore, it must take 300,white shirts, 500 red shirts, 800 yellow shirts and 400 blue shirts.