Tammy said the product of 5/7 and 1 1/4 is 1 3/4

How can you tell that this answer is wrong?
answers:The answer cannot be a mixed number.

This is the correct product.


1 1/4 times a number greater than
cannot result in a product greater than the number.


5/7 times a number greater than
cannot result in a product greater than the number.

1 answer

To determine if Tammy's answer is wrong, we should first calculate the actual product of \( \frac{5}{7} \) and \( 1 \frac{1}{4} \).

  1. Convert \( 1 \frac{1}{4} \) to an improper fraction: \[ 1 \frac{1}{4} = \frac{4}{4} + \frac{1}{4} = \frac{5}{4} \]

  2. Now, multiply \( \frac{5}{7} \) by \( \frac{5}{4} \): \[ \frac{5}{7} \times \frac{5}{4} = \frac{5 \times 5}{7 \times 4} = \frac{25}{28} \]

  3. We should convert \( \frac{25}{28} \) to a mixed number to compare with \( 1 \frac{3}{4} \):

    • Since \( 25 \) is less than \( 28 \), \( \frac{25}{28} \) is less than 1. Thus, it cannot be written as a mixed number greater than or equal to \( 1 \).

Now we analyze Tammy's assertion:

  • Tammy claimed the product is \( 1 \frac{3}{4} \), which is equal to \( \frac{7}{4} \) as an improper fraction. Notice that \( \frac{7}{4} \) is greater than \( 1 \).
  • Since \( \frac{25}{28} \) is less than \( 1 \), this shows that the product cannot be \( 1 \frac{3}{4} \) (since that would imply a value greater than \( 1 \)).

Now let’s review the options provided:

  1. The answer cannot be a mixed number.
  2. This is the correct product.
  3. \( 1 \frac{4}{4} \) times a number greater than cannot result in a product greater than the number.
  4. \( \frac{5}{7} \) times a number greater than cannot result in a product greater than the number.

Correct Choice:

The best choice to demonstrate why Tammy's answer is wrong is: "5/7 times a number greater than cannot result in a product greater than the number."

This is relevant to the scenario because multiplying a fraction (less than 1) by \( 1 \frac{1}{4} \) (which is greater than 1) cannot yield a product that is greater than \( 1 \).