Question

On Monday, a local hamburger shop sold a combined total of 556 hamburgers and cheeseburgers. The number of cheeseburgers sold was three times the number of hamburgers sold. How many hamburgers were sold on Monday?

Answer 1

H = number of hamburgers sold.
c = number of cheeseburgers sold.

we know that "c" is three times the number of "h", thus c = 3h

we also know, the total amount sold for both is 556,  h + c = 556

h + c = 556
c = 3h
thus

h + (3h) = 556 <---- solve for "h" to see how many hamburgers were sold.

what about "c"? well, c = 3h

Answer 2

The number of cheeseburgers sold is three times the number of hamburgers sold...

c=3h

The total number sold is:

c+h=556, using c found earlier in this equation gives you:

(3h)+h=556

4h=556  divide both sides by 4

h=139

So 139 hamburgers were sold on Monday.