The sum of three numbers is 18. The sum of the first and second numbers is 15, and the first number is 3 times the third number. Find the numbers.

3, 6, 9

Step-by-step explanation:

suppose these three numbers are a, b, and c. we can write the following equations:

#1 a+b+c = 18

#2 a+b = 15

#3 a = 3c

if we subtract #2 from #1 we have c = 3. From #3 we have a = 3 (3) = 9. Finally, since a+b+c = 18 we plug in our known values for a and c to obtain b = 6. therefore our three numbers are a = 9, b = 6, c = 3.

9, 6, and 3 are the numbers.

-TTL