Preston is making cookies. he has 4 over 5 cup of flour in a bag. he then used two 1 over 10 cups of flour for his recipe. which of the following best explains the amount of flour left in the bag?

I know that you need to use subtracting.
you also need the make the denominators the same.
Find what the LCM for both numbers 5 and 10.
5: 5, 10, 15
10: 10,20,30
Both have 10 and common.
Do 4/5 x 2/2 and you get 8/10.
Then do 2 1/10 x 1/1 and you get 2 1/10.
then subtract 8/10 by 2  1/10.
You will get 2  7/10 as your answer.

The value of "x" is 15