From the question we are given that;
73 milligrams of cholesterol = 3.8ounce of serving lobster
Required
Amount of cholesterol in 9ounces lobster. To get that we can say;
x = 9 ounces of serving lobster.
Solve for x;
73mg of cholesterol = 3.8 ounces of lobster
x mg of cholesterol = 9 ounces of lobster
Cross multiply;
3.8 * x = 73 * 9
3.8x = 657
x = 657/3.8
x = 172.9mg
Hence a 9 ounce lobster has approximately 172.9milligrams of cholesterol.