Given:
10 Betty Crocker has 25 pounds of chocolate.
So, x Betty Crocker has 15 pounds of chocolate
Using the ratio and proportion to find x
So,

Solve for x

So, she uses 6 Betty Crocker
The remaining = 10 - 6 = 4
So, the percentage will be =

So, the answer will be:
The percentage of chocolate does she have left = 40%