Final answer:
To find out how many yards of fabric is left on the rolls, subtract the total yardage used for the pillow cases from the total yardage of the rolls. The answer is 5 3/8 yards.
Step-by-step explanation:
To find out how many yards of fabric is left on the rolls at JoAnnes Fabric Store after Patricia bought what she needed, we need to subtract the total yardage used for the pillow cases from the total yardage of the two rolls of fabric. The first roll is 10 7/8 yards, which can be written as 10 + 7/8 yards. The second roll is 12 1/4 yards, which can be written as 12 + 1/4 yards.
Each pillow case requires 4 3/8 yards of fabric, which can be written as 4 + 3/8 yards. Since Patricia is making 4 pillow cases, she would need a total of 4 * (4 + 3/8) = 4 * (32/8 + 3/8) = 4 * 35/8 = 35/2 yards of fabric.
To find out how much fabric is left on the rolls, we subtract the total yardage used (35/2 yards) from the total yardage of the rolls (10 + 7/8 yards + 12 + 1/4 yards). Calculating this, we have (10 + 7/8 + 12 + 1/4) - (35/2) = (10 + 7/8 + 12 + 1/4) - (17 + 1/2) = 22 + 7/8 - 17 - 1/2 = 22 - 17 + 7/8 - 1/2 = 5 + 7/8 - 1/2 = 5 + 7/8 - 4/8 = 5 + 3/8 = 5 3/8 yards of fabric left on the rolls.