Let one number be x and the other number be y
one number added to three times another number is 24.
x + 3y = 24
Five times the first number added to three times the other number is 36
5x + 3y = 36
x + 3y =24 ----- (1)
5x + 3y = 36 --- (2)
(2) - (1):
5x - x = 36 - 24
4x = 12
x = 3 ---- sub into equation (1)
3 + 3y = 24
3y = 24 - 3
3y = 21
y= 7
Ans: first number = 3, second number = 7