The sum of three numbers is

7. The third number is 3 times the second. The first number is 5

less than the second. What are the numbers?

The information that is given to us:

x+y+z=7

z=3y

x=y-5

We can now substitute each letter and work it out:

(y-5) + y + (3y) = 7

y+y+3y=7+5

5y=12, then divide each side by 5 and you'll get: Y=2.4

Once you know the value of Y, you substitute Y again:

Z=3 (2.4) - > Z=7.2

X=2.4-5-> X = - 2.6

Finally, to make sure this is the correct answer, you add up everything and it should be the given answer:

-2.6+2.4+7.2=7

I hope this was useful!