Arectangle with a perimeter of 30 centimeters is twice as long as it is wide. what is the area of the rectangle in square centimeters?

Take the small side as x, the longer side is twice as long, i.e. 2x.
Perimeter = 2 small sides plus 2 long sides.
Perimeter = 2x + 2(2x)=30
Perimeter = 6x=30
x=5cm.
So small side is 5cm and long side is 10cm.
Area is one side multiplied by another.
Area = 5 * 10 = 50 square cm.