SOLUTION: The sum of the ages of two brothers is 31 years. They differ in age by 3 years. How is old is each of them?

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Question 1023594: The sum of the ages of two brothers is 31 years. They differ in age by 3 years. How is old is each of them?
Found 2 solutions by Emilym1234, ikleyn:
Answer by Emilym1234(10)   (Show Source): You can put this solution on YOUR website!
Hi! First, I did this in my head-sort-of-way. I'm
Not sure if you had to solve this algebraically, but here you go:
Make a list of all possible solutions to add up to 31.
1,30 2,29 3,28------------------
14,17!! The older one is 17, while the younger one is 14.
They both add to 31, and are exactly 3 years apart!
I hope this helped you, and is it didn't, maybe
Somebody will respond with a much easier or faster way to do this!

Answer by ikleyn(52781)   (Show Source): You can put this solution on YOUR website!
.
The sum of the ages of two brothers is 31 years. They differ in age by 3 years. How is old is each of them?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

x + y = 31,   (1)
x - y =  3.   (2)

Every time when you see two equations like these, add them. You will get

2x = 31 + 3,
2x = 34,

x =  = 17.

Thus the older brother is 17 years old.
The younger brother's age is 17-3 = 14 years.


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