The length of the rectangle is 3 times the width, find the length and width of the rectangle if its perimeter is 48 cm.

To solve this problem, remember that the perimeter of a rectangle is the sum of the lengths of all its sides. Since in a rectangle the opposite sides are equal, then P = 2 * (a + b), where a is the length, b is the width. Let the width of the rectangle be x cm, then the length is 3x cm. Knowing that the perimeter is 48 cm, we will compose the equation.

2 * (x + 3x) = 48;

2 * 4x = 48;

8x = 48;

x = 48/8;

x = 6.

The width is 6 cm and the length is 3 * 6 = 18 cm.

Answer: 6 cm, 18 cm.