If 1/2yd of fabric can make 3 pillowcases, then double the amount (1yd) can make twice the amount of pillowcases (6). Therefore, we need to find out how many times 1/2 = 16 1/2. We can do this by doing the calculation
16 1/2÷1/2=33. That means that 16 1/2yd of fabric can make 3 x 33 = 99 Pillowcases.
Answer: 99 Pillowcases