SOLUTION: The sum of 3 numbers is 18. The sum of the first two numbers is 15. The first number is three times the size of the third number. What are the three numbers?
X+y+z=18
Algebra.Com
Question 532399: The sum of 3 numbers is 18. The sum of the first two numbers is 15. The first number is three times the size of the third number. What are the three numbers?
X+y+z=18
Found 2 solutions by Alan3354, Maths68:
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
The sum of 3 numbers is 18. The sum of the first two numbers is 15. The first number is three times the size of the third number. What are the three numbers?
X+y+z=18
x+y = 15
--> z = 3
---------
x = 3z
x = 9
----------
y = 6
Answer by Maths68(1474) (Show Source): You can put this solution on YOUR website!
Let
Third Number = x
Second Number = y
First Number = 3x
The sum of 3 numbers is 18
x+3x+y=18
4x+y=18............(1)
The sum of the first two numbers is 15
3x+y=15..............(2)
Take (2)
3x+y=15
y=15-3x.........(3)
Put the value of y in (1)
4x+y=18
4x+(15-3x)=18
4x+15-3x=18
x=18-15
x=3
Put the value of x in (2)
3x+y=15
3(3)+y=15
9+y=15
y=15-9
y=6
Third Number = x = 3
Second Number = y = 6
First Number = 3x = 3(3) = 9
RELATED QUESTIONS
The sum of three numbers is 18. The sum of the first and second numbers is 15. The... (answered by Maths68)
The sum of three numbers is 18. The sum of the first and second number is 15, and the... (answered by richard1234,mananth,sophxmai)
The sum of 3 numbers is 29. Twice the first number is 18 more than three times the second (answered by oberobic)
the sum of three numbers is 85. The second number is 8 times the first, while the third... (answered by rfer)
the sum of three numbers is 79 . the second number is 5 times the first , while the third (answered by macston)
The sum of three numbers is 91 the first number is nine more than the second the third... (answered by ankor@dixie-net.com)
The sum of 3 numbers is 15. The second number is double the first. The third number
is 5 (answered by ankor@dixie-net.com)
The sum of three numbers is 114 . The third number is 3 times the first. The second... (answered by ewatrrr)
The sum of three numbers is 111. The third number is 3 times the first. The first number... (answered by Susmitha,MathTherapy,ptfile)