The length of a rectangle is twice it's width. if the perimeter is 60, find the dimensions of the rectangle

Let x be the length of the width(b) of the rectangle.So, length,l = 2x
Then,
Perimeter = 60 units
=> 2(l+b) = 60
=> 2x + x = 60/2
=> 3x = 30
=> x = 30/3
=> x = 10
and, 2x = 2×10 = 20
Hence, length = 20 units
width = 10 units

The first answer is correct