Question

José has 8 1/2 cups of Plaster of Paris powder. If José uses 5 3/5 cups for a sculpture, how much plaster will he have left?

a) 3 9/10 cups
b) 2 9/10 cups
c) 3 1/10 cups
d) None of the above

Answer 1

After converting to improper fractions and finding a common denominator, we can determine that José will have 2 9/10 cups of Plaster of Paris left after making the sculpture. The correct answer is (b) 2 9/10 cups.

Step-by-step explanation:

To determine how much Plaster of Paris José will have left after using some for a sculpture, we need to subtract the amount used from the total amount he has.

José starts with 8 1/2 cups of Plaster of Paris. He uses 5 3/5 cups for a sculpture. To perform the subtraction, we first convert the mixed numbers to improper fractions.

8 1/2 cups is the same as (8 × 2) + 1 = 16 + 1 = 17/2 cups.
5 3/5 cups is the same as (5 × 5) + 3 = 25 + 3 = 28/5 cups.

Now, we find a common denominator, which is 10 in this case, and subtract:

• 17/2 becomes 85/10 after multiplying both numerator and denominator by 5.
• 28/5 becomes 56/10 after multiplying both numerator and denominator by 2.
• 85/10 - 56/10 is 29/10, which is equal to 2 9/10 cups.

Therefore, José will have 2 9/10 cups of Plaster of Paris left after making the sculpture. The correct answer is (b) 2 9/10 cups.