Question 569549
m=my age  d=daughter age
{{{(m-5)+(d-5)=(1/3)(5((m+d)/2))}}}
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 {{{(m-5)+(d-5)}}} 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){{{(m+d)/2}}} 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){{{(5((m+d)/2))}}} is same as "five times the average of the present ages of my daughter and my self" multiplying by 5
4){{{(1/3)(5((m+d)/2))}}} is same as "a third of five times the average of the present ages of my daughter and my self" multiplying by a third
 
.
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{{{d+5=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.

{{{(m-5)+(d-5)=(1/3)(5((m+d)/2))}}} substitute {{{10}}} for {{{d}}}
{{{(m-5)+(10-5)=(1/3)(5((m+10)/2))}}} solve for {{{m}}}
{{{(m-5)+(5)=(1/3)((5m+50)/2)}}} add like terms and distribute the {{{5}}} and {{{1/3}}}
{{{m=(5m+50)/6}}} multiply by {{{6}}} and subtract {{{5m}}} from each side
{{{highlight(m=50)}}}
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check
{{{(45)+(5)=(1/3)(5((60)/2))}}}
{{{(50)=(1/3)(5(30))}}}
{{{(50)=(1/3)(150)}}}
{{{(50)=(50)}}}
correct