One number added to three another number is 24. Five times the first number added to three times the other number is 36. Find the number.

First number = 3.

The other number = 7.

Step-by-step explanation:

I am assuming you mean 'one number added to three times another number is 24'. Let the 2 numbers be x and y.

We have the following system of equations:

x + 3y = 24

5x + 3y = 36

Subtracting the 2 equations (the second minus the first):

4x = 12

x = 3

Substituting x = 3 in the first equation:

3 + 3y = 24

3y = 24 - 3

3y = 21

y = 7.

Step-by-step explanation:

x + 3y = 24

5x + 3y = 36

Like you said, BUT

if you were to subtract the equations

x - 5x = - 4x

Then the 3ys would cancel out. Leaving:

-4x = 12

x would equal - 3