Answer:
48%
Step-by-step explanation:
First, we need to add the amounts together to be able to see what percent of all the cups are dirty. (228 + 247 = 475). Now we can find one percent of 475 we can do this by moving the decimal point two to the left. (4.75). so If 4.75 is 1% we can multiply 4.75 until we get 228.
4.75 x 20 = 95.
4.75 x 40 = 190
4.75 x 45 = 213.75
4.75 x 50 = 237.5
4.75 x 48 = 228
Since every time we multiplied by 1 more we went up 1%. We multiplied by 48 so 48%.
