Question 728141:
Answer by Lisalovemath(2)   (Show Source):
You can put this solution on YOUR website! Zach is two-sevenths of his father's age this year. Zach is 12. How old is his father?
You must write an equality equation. That is, we know two things that both represent Zach's age. They are 2/7n and 12. With this, we can write an equation. Also note that n is the father's age.
2/7n=12
Now, isolate the n with multiplying both sides by the reciprocal of 2/7 which is 7/2.
7/2•2/7n=12•7/2
On the left side of the equal sign, the 7/2 cancels with the 2/7, leaving only the n. On the right side, the 12/1 multiplies with the 7/2 to equal 42.
Thus, we now know the value of n is 42.
n=42
We can check the problem by substituting 42 into our original equation.
2/7n=12
2/7(42)=12
Divide 42 by 2/7.
12=12
We know we have found the correct age for the father. His age is 42.
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