0.75 is greater the 0.0075
This might help it has tons of different problems for your subject.
https://www.wyzant.com/resources/lessons/math/algebra/calculators/proportion
1 people eat 3/8 pound of potato salad lets reoresent it:
x=3/8
Lets say n is the value of how many people ate with 7 people
7x=n
now substitute
7x=n
7(3/8)=n
21/8=n
n=2 5/8
X=12 because 73-3x=61-2x so add 3x to both to make 73=61+X then subtract 61 from both to get 12=X