Answer:
D: 4
Explanation:
1) Make the 1/4 into 5/20 by multiplying top and bottom by 5/5
x/5 - 5/20 = 11/20
2) Move the 5/20 to the other side
x/5 = 11/20 + 5/20
3) Add the 2 fractions on the right
x/5 = 16/20
4) Make the fraction on the right have a denominator of 5 by dividing top and bottom by 4/4
x/5 = 4/5
5) Multiply both sides by 5
x = 4
The missing numerator is 4.