The sum of 2 numbers is 260 and one number is 3 times the other. Find the number

Let one of the number be x.

The sum of the 2 number is 260

⇒ The other number is 260 - x

The number is 3 times the other

⇒ x = 3 (260 - x)

Solve x:

x = 3 (260 - x)

x = 780 - 3x

4x = 780

x = 195

x = 195

260 - x = 260 - 195 = 65

Answer: The numbers are 65 and 195.