The food service gave out 80 samples, which is 4 fewer than 70% of the total number of samples they prepared. Lets make x the total number of samples they prepared.
So lets write it as an equation
80 = (70% of x) -4
70% converts to a decimal by moving the decimal point 2 spaces up, so it is 0.7
80 = 0.7x-4
Add 4 to both sides of the equation
84 = 0.7x
Divide both sides by 0.7 to isolate the x
x = 120
The food service prepared 120 samples.
