SOLUTION: the sum of three numers is 72. The first number is half the second, and the third number is three times the second one. what is the value of the first number?

Question 930499: the sum of three numers is 72. The first number is half the second, and the third number is three times the second one. what is the value of the first number?
Answer by algebrahouse.com(1659) (Show Source): You can put this solution on YOUR website!
x = second number
x/2 = first number
3x = third number

x + x/2 + 3x = 72 {sum of the three numbers is 72}
2x + x + 6x = 144 {multiplied entire equation by 2 to eliminate fractions}
8x = 144 {combined like terms}
x = 18 {divided each side by 8}
x/2 = 9 {substituted 18, in for x, into x/2}

9 is the first number

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