First, we need to calculate the total cost of the jacket and the blouse:
- Jacket: $15.99
- Blouse: $7.49
Now, let's add these two amounts together:
\[ 15.99 + 7.49 = 23.48 \]
Next, Tamara pays with two $20 bills:
\[ 2 \times 20 = 40 \]
Now, we subtract the total cost from the amount she paid to find out how much change she will receive:
\[ 40 - 23.48 = 16.52 \]
Therefore, Tamara should expect $16.52 in change.