Let's denote the amount of money Su En has as \( S \), the amount Elaine has as \( E \), and the amount Lee Ling has as \( L \).
From the problem, we know:
- \( S = 825 \)
- \( 0.8S = 1.5E \)
Substituting \( S \) into the second equation:
\[ 0.8 \times 825 = 1.5E \]
Calculating the left side:
\[ 0.8 \times 825 = 660 \]
So, we have:
\[ 660 = 1.5E \]
To find \( E \), divide both sides by 1.5:
\[ E = \frac{660}{1.5} = 440 \]
Now we can find Lee Ling's amount, \( L \). According to the problem, Lee Ling has 50% of the total amount of money that Su En and Elaine have together:
\[ L = 0.5(S + E) \]
Calculating \( S + E \):
\[ S + E = 825 + 440 = 1265 \]
Now substituting this into Lee Ling's equation:
\[ L = 0.5 \times 1265 = 632.5 \]
Now we can find the total amount of money that all three girls have:
\[ \text{Total} = S + E + L = 825 + 440 + 632.5 \]
Calculating the total:
\[ 825 + 440 = 1265 \] \[ 1265 + 632.5 = 1897.5 \]
Thus, the total amount of money that the three girls have is:
\[ \boxed{1897.5} \]