Posted by TUHITUHI on Saturday, October 6, 2012 at 12:19pm.
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
Related Questions
math - Sanjeev is twice as old as his son.If after four years he will be four ...
Kathie - In four years' time, a father will be three times as old as his son...
algebra - A man is 4 times as old as his son.After 16 years he will be only ...
math - Mary, who is sixteen years old, is four times as old as her brother. How...
Math - In five years,Emma will be three years more than twice as old as her son...
Math - Bernie is the oldest of the four Bryant brothers. Bobby is twice as old ...
MATH - 1. A father is three times as old as his son. Five years ago the sum of ...
math - Michel is twice as old as his sister sylvia. In four years three times ...
math - When a woman is as old as her father is now, she will be five times as ...
math - Jack is twice as old as he was 5 years ago. His mother was then six times...
For Further Reading
