Arecipe for salsa use a 65% tomatoes if a vast contains 5.2 cups of tomatoes how large is the batch of salsa

5.2 cup is the same as 65% of what number
Now let's put that into math:

5.2 = 65% of n
5.2 = .65n

Divide both sides by .65 to get n by itself

5.2 = .65 n
.65     .65
n= 8 cups in this batch of salsa

Notice that dividing by .65 (a number less than 1) made the 5.2 actually increase to 8.  Division does not always make thing smaller.