# Age and system of linear equations

by MARIA
(SALT LAKE CITY, UT)

Alvin's age is three times Elga's age. The sum of their ages is " 40 ". What is Elga's age?

Let x be Alvin's age

Let y be Elga's age

x + y = 40

x = 3y

Replace x = 3y into x + y = 40

We get 3y + y = 40

4y = 40

4y/4 = 40 / 4

y = 10

So Elga is 10 years old

Alvin's age is x = 3y = 3 times 10 = 30

### Comments for Age and system of linear equations

Average Rating

 Apr 04, 2015 Rating Mathematics problem by: Anonymous I think it is algebra problem. I don't know the answer. I think every college student face the same problem.

 Jan 05, 2015 Rating Nice one by: Anonymous That was an interesting problem. I finally solved one problem without much effort. I love solving high school mathematics problems. It is not that I’m an expert. But I love doing it during my free time. Keep updating more problems.

 Feb 03, 2014 Rating nice by: PCB manufacture Thanks for sharing

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