Question 1066631
There are really two ideas here at play.

First, you need to convert the mixed fraction to an improper fraction. 

So 1 1/3 cups of tomato sauce is really like 3/3 cups + another 1/3 cups. So 4/3 cups.  And similarly, if Julia needs 2 1/2 times more, then she needs 4/2 + 1/2 times more... or 5/2.

So now that we have 1 1/3 =  4/3
and  2 1/2 = 5/2, we can now multiply the improper fractions together.

Remember that it is a matter of just multiplying numerators and denominators and then simplifying the fraction.

So {{{4/3 * 5/2 =  20/6}}}

We are almost done, but we need to get the fraction back to a mixed number since that was the format we were given.

First off, 20/6 can be reduced to 10/3.  If we divide 3 into 10 we get 3 with a remainder of 1. So, the answer is 3 1/3 cups of tomato sauce. You can also think of 10/3 as  9/3 + 1/3, so  3 1/3.