Thread: age related question

Is this question right or some information is missing in it ?

In 5 years time father will be 3 times as old as his son. four years ago father was 6 times as old as his son.

Find their present age ?

Can anyone help me solve it if its correct

Originally Posted by haftakhan

Is this question right or some information is missing in it ?

In 5 years time father will be 3 times as old as his son. four years ago father was 6 times as old as his son.

Find their present age ?

Can anyone help me solve it if its correct

let f = father's present age

s = son's present age

In 5 years time father will be 3 times as old as his son

f + 5 = 3(s + 5)

four years ago father was 6 times as old as his son

f - 4 = 6(s - 4)

yes, the system of equations has a unique solution.

Originally Posted by haftakhan

Is this question right or some information is missing in it ?

In 5 years time father will be 3 times as old as his son. four years ago father was 6 times as old as his son.

Find their present age ?

Can anyone help me solve it if its correct

With these problems it's always good to write down what you know using variables. Let the father's age now be and the son's age now be .
Now we can write a number of equations based on what we're told:

In 5 years time father will be 3 times as old as his son:

four years ago father was 6 times as old as his son:

You now have a pair of simultaneous equations in x and y so you can solve it. In this case it would be easier to use elimination by taking the second equation from the first