Question 873206
the avg age of man and his twin sons born on the same day is 30 yr.
 ratio of the ages of father to one of his sons is 5:2
. What is fathers age
: 
Let f = father's age
Let s = son's age
:
Write an equation for each statement:
:
"the avg age of man and his twin sons born on the same day is 30 yr."
{{{(f+2s)/3 }}} = 30
multiply both sides by 3
f + 2s = 90
f = (90-2s); use this form for substitution
:
ratio of the ages of father to one of his sons is 5:2.
{{{f/s}}} = {{{5/2}}}
cross multiply
5s = 2f
Replace f with (90-2s)
5s = 2(90-2s)
5s = 180 - 4s
5s + 4s = 180
9s = 180
s = 180/9
s = 20 yrs is the age of the twins now
then
90 - 2(40) = 50 yrs is the father's age now
:
:
you can check these solutions in both statements.