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Question 128447: The sum of three numbers is 5. The sum of the first and second number is 3, and the first number is one more than three times the third number. How many of the numbers are even numbers?
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! Let's just write an equation for each phrase and see where that takes us:
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"The sum of three numbers is 5. "
x + y + z = 5
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"The sum of the first and second number is 3,"
x + y = 3
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"the first number is one more than three times the third number."
x = 3z + 1
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If we know the numbers we know if they are odd or even:
Using the 1st two equations:
x + y + z = 5
x + y + 0 = 3
---------------Subtracting eliminates x & y, giving us z
0 + 0 + z = 2
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Find x using the 3rd equation:
x = 3z + 1
x = 3(2) + 1
x = 6 + 1
x = 7
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Find y using x + y = 3
7 + y = 3
y = 3 - 7
y = -4
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Our numbers are 7, -4, 2
How many of the numbers are even numbers? Two of them are even
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