Question

The formula for relating a man's shoe size S and the length of his foot L in inches is

S3L
26. Find the length of a man's foot if he wears a size 12 shoe.

Answer 1

the length of his foot in inches is 12

Answer 2

12 5/6 inches

Explanation:

You want to find the value of L when S=12 1/2, using the formula S = 3L -26.

Foot length

You can substitute for S in the formula before or after you solve for L. Here, we'll solve for L first:

S +26 = 3L . . . . add 26 to both sides

(S +26)/3 = L . . . . divide both sides by 3

Substituting 12 1/2 for S, this becomes ...

L = (12 1/2 +26)/3 = (38 1/2)/3 = (77/2)/3 = 77/6 = 12 5/6

A man's foot is 12 5/6 inches long if he wears a size 12 1/2 shoe.