Answer:
11/4 = 5/4
If you need 5/4 cups of sugar to make 20 cookies or in other words,
For 20 cookies you need 5/4 cups of sugar then
for 14 cookies you will need: 14 * (5/4)/20 = 7/8 cups of cookies
if you like a very sweet cookies then you can add a bit more sugar to make it 1 full cup of suger