Given that the width of the rectangular piccture is:
Where "l" is the length of the picture.
You know that the perimeter is:
The formula for calculating the perimeter of a rectangle is:
Where "l" is the length and "w" is the width.
Therefore, you can substitute the perimeter and the width into the formula, in order to find "l":
Now you can solve for "l":
Hence, the answer is: