If the ratio is 5:8:2, then we have altogether 15 parts of the value (because 5 + 8 + 2 = 15). First of all we need to find out how much is one part of the value, so we have to divide $75,000 by 15.
$75,000 ÷ 15 = $5000
The first daughter will get 5 * $5,000 = $25,000
The second daughter will get 8 * $5,000 = $40,000
The third daughter will get 2 * $5,000 = $10,000
$25,000 + $40,000 + $10,000 = $75,000, so it's correct :)
