After hemming a skirt 1/2 inch, pat realized she needed to hem a total of 7/8 inch. what length must she hem in addition to what she has already done? a) 11/8 inch b) 6/8 inch c) 1/2 inch d) 3/8 inch

1/2 inch is equivalent to 4/8 inch. 

So subtract 7/8 by 4/8 which equals to 3/8.

So the answer is D. 

The answer would be D 3/8 inch

B. 5.375

Explanation:
First, find what the value of R is.
R is between 5 1/4 and 5 1/2, and every two increments are a total of 1/4 so 1/4 ÷ 2 = 1/8 
5 1/4 + 1/8 = 5 3/8 
R = 5 3/8 

Now find what this value is in decimal form. We know it is 5 point something, so just divide 3 by 8 to find the rest of the decimal. 
3 ÷ 8 = .375 so 5.375 is your answer.