Question

Mom baked a vanilla tea cake. The recipe called for 1 cup of flour, $\frac{1}{2}$ cup of sugar, and $\frac{1}{2}$ cup of butter. Aunt Fenny loved the cake and decided to bake it when she had guests over. If her recipe uses 3 cups of flour, can you help her with the amount of sugar and butter she needs?

• A. 3 cups of sugar, 3 cups of butter
• B. 1$\frac{1}{2}$ cups of sugar, 1$\frac{1}{2}$ cups of butter
• C. 2 cups of sugar, 2 cups of butter
• D. 2 cups sugar, 2 cups butter

Answer 1

The correct option is B 1$\frac{1}{2}$ cups of sugar, 1$\frac{1}{2}$ cups of butter

For 1 cup of flour, Mom uses $\frac{1}{2}$ a cup of butter and $\frac{1}{2}$ a cup of sugar.
She uses $\frac{1}{2}$ the quantity of sugar and butter compared to the quantity of flour.
Going by the recipe, if 3 cups of flour are used by aunt Fanny,
the quantities of sugar and butter would be $\frac{1}{2}$ of 3:
$=\frac{1}{2}\times 3$
$=\frac{3}{2}$

Converting this improper fraction to mixed fraction, we get:
$=1\frac{1}{2}$ cups of sugar