# math

posted by .

Sanjeev is twice as old as his son.If after four years he will be four times as old as his son was 9 years ago ,how old is each now ??

• math -

Let's let J represent Sanjeev and x represent his son.

If J is twice as old as S then the equation is 2x=J

After four years, so J+4, he is four times as old as his son, so 4x, was 9 years ago, so x-9, if you combine all the parts of that statement you get the equation: 4(x-9)= J+4.

So now you have two different equations:
2x=J
4(x-9)=J+4

So now you just substitute. We know that J=2x from the first equation so substitute 2x in for J in the second equation and solve for x:

4(x-9)=(2x)+4
4x-36=2x+4
2x-36=4
2x=40
x=20

so now we know that the son is 20 years old. Then plug in 20 for x in the first equation to find Sanjeev's age:

2(20)=J
40=J

So Sanjeev is 40

## Similar Questions

1. ### Kathie

In four years' time, a father will be three times as old as his son. Six years ago, he was seven times as old as his son. How old are they now?
2. ### math

Sanjeev is twice as old as his son.If after four years he will be four times as old as his son was 9 years ago ,how old is each now ?
3. ### Math

In five years,Emma will be three years more than twice as old as her son. Five years ago,she was two years less than five times, as old as her son. How old Emma now?
4. ### algebra

The combined age of a father and his two sons is 50 years. Four years ago the father was eight times as old as his older son. Four years from now he will be 4 times as old as his younger son. Find the age of each at present. I found …
5. ### math

six years ago, jim was four times as old as Fe. In four years, he would be twice as old as fe.How old are they now?
6. ### Math

Six years ago, Jim was four times as old as Fe. In four years, he would be twice as old as Fe. How old are they now?
7. ### algebra

Seven years ago a women was four times old as her sons age at that time.In seven years years from now the mother will be twice as old as her son would be then.Find their present ages. Answer
8. ### algebra

in four years's time a father will be three times as old as his son. Six years ago,he, he was seven times as old as his son. how old are they now?
9. ### math

Ten years ago,father was twelve times as old as his son and ten years from now,he will be twice as old as his son. Find the present age
10. ### Maths

A father was three times as old as his son fifteen years ago and four times his sons age nineteen years ago. When was the father twice as old as the son?

More Similar Questions