The sum of two numbers is 72, and one of them is 3 times the other. Find these numbers.

Let the smaller number be equal to X, and the larger number equal to Y.

Let us compose, from the condition, a system of two equations and solve it.

X + Y = 72;

Y = 3 * X;

Substitute Y = 3 * X in the first equation and find the value of the smaller number.

X + 3 * X = 72;

4 * X = 72;

X = 72/4;

X = 18;

Substitute the X value in the second equation.

Y = 3 * 18 = 54.

Answer: The smaller number is 18, the larger number is 54.

One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.