Answer:
The answer is 13!!!
Explanation:
Not only are you adding the fact that he returns and buys three times the same order, you need to add the amount he spent the first time!
Like this:
0.6 + 0.6 + 0.7 + 0.45 + 0.45 + 0.45 = 3.25
This is how much he spent the first time. Now, you need to multiply 3.25 by 4 because he went back for three times the order, which will give you 13.
3.25 * 4 = 13
9.75 is what you get for only 3 of the order, and he bought 4