To find the value of the investment at the end of the month, we need to subtract the loss from the initial value of the investment.
Initial value of the investment: \( 48.45 \) dollars
Loss: \( 13.80 \) dollars
We can calculate the end value as follows:
\[ \text{End value} = \text{Initial value} - \text{Loss} \] \[ \text{End value} = 48.45 - 13.80 \] \[ \text{End value} = 34.65 \]
Thus, the value of the investment at the end of the month is \( 34.65 \) dollars.