Question 141359
How do I solve using a system of two linear equations in two variables?
Barry is 8 years older than his sister. In 3 years, he will be twice as old as she will be then. How old is each now?
:
Let x = B's age now
Let y = S's age now
:
Write an equation for the statement,"Barry is 8 years older than his sister."
x = y + 8
or
x - y = 8
:
The same for this statement," In 3 years, he will be twice as old as she will be then.
(x+3) = 2(y+3)
x + 3 = 2y + 6
x = 2y + 6 - 3
x = 2y + 3
x - 2y = 3
:
The system, two equations two variables
x -  y = 8
x - 2y = 3 
------------ subtracting eliminates x
0 + y = 5 yrs is sister's age now
:
I'll let you find Barry's age