SOLUTION: 5 years ago the sum of my age and my daughters age was a third of five times the average of the present ages of my daughter and my self if my daughter will be 15 years old in 5 yea

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Question 569549: 5 years ago the sum of my age and my daughters age was a third of five times the average of the present ages of my daughter and my self if my daughter will be 15 years old in 5 years how old is tim now
Answer by JBarnum(2146) About Me  (Show Source):
You can put this solution on YOUR website!
m=my age d=daughter age
%28m-5%29%2B%28d-5%29=%281%2F3%29%285%28%28m%2Bd%29%2F2%29%29
im going to explain the above equation as its second nature for me but for some this may be hard to get this equation from words:
1) the %28m-5%29%2B%28d-5%29 is same as "5 years ago the sum of my age and my daughters age" m and d are the present ages so subtracting 5 years from each of them makes it 5 years ago
2)%28m%2Bd%29%2F2 is same as "the average of the present ages of my daughter and my self" average is adding both ages and dividing them by the number of ages added
3)%285%28%28m%2Bd%29%2F2%29%29 is same as "five times the average of the present ages of my daughter and my self" multiplying by 5
4)%281%2F3%29%285%28%28m%2Bd%29%2F2%29%29 is same as "a third of five times the average of the present ages of my daughter and my self" multiplying by a third

.
.
d%2B5=15 "my daughter will be 15 years old in 5years" so d=10
who is tim?
dumb question we dont know who tim is and what tim's age is so its an incomplete question but if you wanted to find your age it is as follows.
%28m-5%29%2B%28d-5%29=%281%2F3%29%285%28%28m%2Bd%29%2F2%29%29 substitute 10 for d
%28m-5%29%2B%2810-5%29=%281%2F3%29%285%28%28m%2B10%29%2F2%29%29 solve for m
%28m-5%29%2B%285%29=%281%2F3%29%28%285m%2B50%29%2F2%29 add like terms and distribute the 5 and 1%2F3
m=%285m%2B50%29%2F6 multiply by 6 and subtract 5m from each side
highlight%28m=50%29
.
check
%2845%29%2B%285%29=%281%2F3%29%285%28%2860%29%2F2%29%29
%2850%29=%281%2F3%29%285%2830%29%29
%2850%29=%281%2F3%29%28150%29
%2850%29=%2850%29
correct