Question

a triceatops has to children. one is 3 times older than the other. Together, their age is 50 months how old are they?

Answer 1

To solve this problem, create two equations with x and y. The pieces of information that we know are that the first child is 3 times older than the second child. Therefore if we assign child #1 the variable of x and child #2 the variable of y, we could get the following equation: 

3x = y 

Now, we also know that together their ages equal 50 months. Therefore:

x + y = 50 (months) 

So, using these two equations you can use either substitution or elimination to find the values of x and y. You would first need to rearrange the first equation to 3x - y = 0 (just moving the y to the other side). 

Then, you could add the equations together as followed: 

3x - y = 0 
x  + y = 50 
___________
4x = 50 
x   = 12.5

And then fill that value in to one of the equations to find y.

3x = y 
3(12.5) = y 
y = 37.5

So, one child is 12.5 months old and the other is 37.5 months old!