D=rt
So you're going to plug in the values listed: r= 9 1/2 and t=1 3/4
This will give you:
d=(9.5)(1.75)
Then you solve:
d=16.625
You should probably convert that decimal answer into a fraction since you're question gave it to you as a fraction.
Answer:
Random, because he surveyed 30 <em>random</em> shoppers
Difference=subtract sum=add. just answering so you don't waste points :-)
The Answer would be x=72. Why? Because

is your %. You Cross multiply 240 * 30 = 100x
240 time 30 = 7200. you want x to be alone so you do 7200 divided by 100 equaling 72. So you get x=72.
Diameter = 2*(radius)
The radius is half of the diameter, so if you were given the radius and need to find the diameter, multiply the radius by two. If you were given the diameter and need to find the radius, divide the dimaeter by two