for every two M&Ms you buy, you get two free. If one M&Ms cost .79 cents how many can you buy for 6 dollars?
I assume that you are referring to bags of M&Ms. Otherwise, I wouldn't buy any.
.79x ≤ 6.00
x ≤ 7.59
7 * 4 = ?
.79x ≤ 6.00
x ≤ 7.59
7 * 4 = ?