SOLUTION: a man is four times as old as his son,in four years time,he will be three times as old. what are their ages?

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Question 979465: a man is four times as old as his son,in four years time,he will be three times as old. what are their ages?
Answer by ikleyn(52832)   (Show Source): You can put this solution on YOUR website!

Let  x  be the man's age now,  and let  y  be the son's age now.

Then we have an equation

x = 4y,

according to the condition.

In  4  years the man's age will be  x+4,  and his son's age will be  y+4.
Thus we have the second equation

x + 4 = 3*(y+4),

according to the condition.

So,  we need to solve this system of linear equations

.

To solve it,  substitute  x  from the first equation to the second one.  You will have

4y + 4 = 3*(y+4),
4y + 4 = 3y + 12,
y = 12 - 4,
y = 8.

Thus the son age is  8  years now.
Then the man's age is  8*4 = 32  years now.

The problem is solved.


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