Answer:
$40
Step-by-step explanation:
Let the amount of money she has at first be $x.
She put 1/4 for savings, this means she decides to spend 3/4. The 3/4 is equivalent to (3/4)x
Now, she puts half of the money not saved to pay back her sister and has $15 left.
This means the (3/4)x is equivalent to $30. This is because she used half which is $15 to pay back her sister.
Now, since (3/4)x equals 30, we calculate x
(0.75)x = 30
x = 30/0.75 = $40
She originally had $40