Final answer:
To determine the declared amount, multiply the family's cash reserve of $725 by 3/8, which equals $271.875. Rounded to the nearest cent, the family must declare $271.88.
Step-by-step explanation:
The question asks how much money a family must declare if they need to report 3/8 of their cash reserves of $725.
To find this amount, the cash reserves should be multiplied by 3/8.
Calculation:
$725 × rac{3}{8} = $271.875
Thus, the family must declare $271.875. If we are dealing with currency, this value might be rounded to the nearest cent, which would make it $271.88.