At a sports camp there us one counselor for wvery 12 campers if there is 156 campers attending the camp which equivalent ratio vould be used to find the number of counselors

One counselor to 12 campers is your ratio.
1:12.
Now, we have 156 campers, so let's divide 156 by 12 to see how many counselors there would be.
156/12 = 13.
So, there are 13 counselors present.
Basically, we scaled up the original ratio of 1:12 to x:156.
x was 13.