The length and width of the rectangle together are 21 cm. What is the length and width

The length and width of the rectangle together are 21 cm. What is the length and width of the rectangle if the length is 6 times its width?

To solve this problem, we introduce two conditional variables “X” and “Y”, through which we denote the length and width of the rectangle, respectively.

Then, based on the data of the problem, we will compose the following equations: 1) X + Y = 21;

2) X / Y = 6.

Solving a system of two equations with two unknowns, we obtain X = 6Y.

Substituting X in the first equation, we get 6Y + Y = 21 or 7Y = 21 or Y = 3 centimeters.

Therefore, X will be equal to 6 x 3 = 18 centimeters.

Answer: the length of the rectangle is 18 centimeters, the width is 3 centimeters.