two years ago A man was five times as old as his son 2 years later his age will be 8 more than three times the age of his son find their present ages
Answers
Let the age of the man be x yrs.
and the age of his son be y yrs.
Before 2 years
x-2 = 5(y-2)
=>x-5y = -8..... (i)
After 2 years
x+2 = 8+3(y+2)
=>x-3y = 12.....(ii)
Subtracting i and ii, we get
(x-5y) - (x-3y) = -8-12
=> y = 10
Putting the value of y in eq. i , we get
x = 42
So the age of man = 42yrs
and the age of son = 10yrs.
Let the age of father is x years and that of son is y years.
Then by the given question,
x-2=5(y-2)
or, x-5y=-10+2
or, x-5y=-8
or, x=5y-8
x+2=3(y+2)+8
or, x-3y=6+8-2
or, 5y-8-3y=12
or, 2y=12+8
or, y=20/2
or, y=10
then x=5y-8=50-8=42
Then, the age of father is 42 yrs. and the age of son is 10 yrs.
Alternately,
Let t f = father's present age
let s = son's age
:
Write an equation for each statement, simplify as much as possible.
:
" two years ago , a father was five times old as his son ."
f - 2 = 5(s-2)
f - 2 = 5s - 10
f = 5s - 10 + 2
f = 5s - 8
"two years later from today his age will be 8 years more than three times the age of his son "
f + 2 = 3(s+2) + 8
f + 2 = 3s + 6 + 8
f = 3s + 14 - 2
f = 3s + 12
replace f with (5s-8), from the 1st statement
5s - 8 = 3s + 12
5s - 3s = 12 + 8
2s = 20
s = 10 yrs is the son's age
then
f = 5(10) - 8
f = 42 yrs is father's age
:
So,finally the present ages of son and father are 10 and 42 respectively....