Danny's lemon cookie recipe calls for 3 1/8 cups of sugar. How much sugar would Danny use to make 1/5 of a batch of cookies?

Write your answer as a fraction or as a whole or mixed number.

cups

1 answer

To find out how much sugar Danny would use to make \( \frac{1}{5} \) of a batch of cookies using 3 \( \frac{1}{8} \) cups of sugar, we can follow these steps:

  1. Convert the mixed number \( 3 \frac{1}{8} \) into an improper fraction. \[ 3 \frac{1}{8} = 3 \times 8 + 1 = 24 + 1 = 25 \quad \text{(so, it becomes } \frac{25}{8}\text{)} \]

  2. Calculate \( \frac{1}{5} \) of \( \frac{25}{8} \). \[ \frac{1}{5} \times \frac{25}{8} = \frac{25 \times 1}{8 \times 5} = \frac{25}{40} \]

  3. Simplify \( \frac{25}{40} \):

    • The greatest common divisor (GCD) of 25 and 40 is 5. \[ \frac{25 \div 5}{40 \div 5} = \frac{5}{8} \]

Therefore, Danny would need \( \frac{5}{8} \) cups of sugar to make \( \frac{1}{5} \) of a batch of cookies.

So the final answer is:

\[ \frac{5}{8} \text{ cups} \]