A rectangular room is twice as long as it is wide, and its perimeter is 54 meters. Find the width of the room
Remember that
the perimeter of a rectangle is equal to
P=2(L+W)
we have
P=54 m
L=2W
substitute in the formula of perimeter
54=2(2W+W)
solve for W
54=2(3W)
54=6W
W=9 meters