Answer:
9 shirts
Step-by-step explanation:
0.5 in percentage form is 50%.
50% + 20% is 70%. You want to find out the percentage that represents the neither black or blue, so do 100% minus 70%. 100% - 70% is 30%.
Use this ratio: 30/100 = X/30
Simplify the ratio to: 3/10 = X/30
Cross multiply: 90 = 10X
Divide both sides by 10: 90/10 = 10X/10
9 = X
