Hi,

the perimeter of a rectangle is 156, width is 20% the length
Let x represent the length, then width is .20x
Question states***
2x + 2(.20x) = 156
Solving for x
2.4x = 156
x = 65, the length. the width is 13 units
CHECKING our Answer***
2*65 + 2*13 = 156