Question 278836
Paul's father is 2 years older than his mother.
 Paul's age is one third his father's age.
 When Paul was born, the sum of his parent's age was 42.
 How old are Paul's parents now?
:
Let f = father's present age
Let m = mother's present age
Let p = paul's present age
:
"Paul's father is 2 years older than his mother."
f = m - 2
or
m = f + 2
:
"Paul's age is one third his father's age."
p = {{{1/3}}}f
:
" When Paul was born, the sum of his parent's age was 42."
(f-p) + (m-p) = 42
:
In the above equation, replace p with {{{1/3}}}f and m with (f+2)
(f - {{{1/3}}}f) + (f+2) - ({{{1/3}}}f) = 42
:
{{{2/3}}}f + f + 2 - {{{1/3}}}f = 42
;
{{{2/3}}}f + f - {{{1/3}}}f = 42 - 2
:
{{{2/3}}}f + f - {{{1/3}}}f = 40
:
{{{2/3}}}f + {{{2/3}}}f = 40
multiply by 3:
2f + 2f = 3(40)
4f = 120
f = {{{120/4}}}
f = 30 yrs 
and
m = 32
:
Father is 30, mother is 32
;
:
Check solution by finding P's age
{{{1/3}}}(30) = 10 yrs is Paul,s age
:
Check solution in the statement:
"" When Paul was born, the sum of his parent's age was 42."
(30-10) + (32-10) = 42