210 is what percent of 500?

The answer is 42

Explanation:

Step 1: We make the assumption that 500 is 100% since it is our output value.

Step 2: We next represent the value we seek with X.

Step 3: From step 1, it follows that 100%= 500.

Step 4: In the same vein, X%= 210.

Step 5: This gives us a pair of simple equations:

100%= 500(1)
X%=210(2)

Step 6: By simply dividing equation 1 by equation 2 and taking note of the fact that both the LHS
(left hand side) of both equations have the same unit (%); we have

100%/X%= 500/210

Step 7: Taking the inverse (or reciprocal) of sides yields
X%/100= 210/500
X= 42%