Answer:
5
Explanation:
Firstly, we know that the number of $10 bill is 1/10 of $1 and 1/5 times that of $5 bills.
We also know that the amount of $10 bills equal that of $1 bills and the total amount of bills we have is $225.
Now, let the amount of $10 be x. This means the amount of $1 bill is 10x and the amount of $5 bill is 5x.
Mathematically:
$10[x] + $1[10x] + $5[5x] = $225
$10x + $10x + $25x = $225
$45x = $225
x = $225/$45 = 5
This means she have only 5 $10 bills