To find out how many weeks \( w \) it will take to have \( $240 \) in your bank account, we can start with the equation you provided:
\[ b = 80 + (15 + 8)w \]
First, simplify the equation:
\[ b = 80 + 23w \]
Now, we want to find \( w \) when \( b = 240 \):
\[ 240 = 80 + 23w \]
Next, subtract \( 80 \) from both sides:
\[ 240 - 80 = 23w \]
\[ 160 = 23w \]
Now, divide both sides by \( 23 \):
\[ w = \frac{160}{23} \approx 6.96 \]
Since \( w \) represents the number of weeks, you will need to round up because you cannot have a fraction of a week. Therefore, it will take approximately \( 7 \) weeks to have at least \( $240 \) in your bank account.