Answer:
80 units if the length is equal to x (it is unspecified)
Step-by-step explanation:
Assuming that the length is equal to x, then we know that the length is 10 units long because x = 10.
Since the width is 3 times longer than the length, we can also find that the width is 30 units long because 3 x 10 = 30.
Now, we can use the perimeter formula to find the perimeter of the rectangle.
The perimeter formula is P = 2 ( L + W ), with L being length and W being width.
Let's just substitute the numbers to find perimeter.
P = 2 ( 10 + 30 )
P = 2 ( 40 )
P = 80
So, the perimeter is 80 units.