If 2x + y = 7 and x + 2y = 10, then (x + y)/3 =  Choose the correct choice from the following choices:  A) 1  B) 4/3  C) 17/9  D) 18/5  E) 4
We have two equations:   2x + y = 7   x + 2y = 10   Notice that something nice happens when we ADD them. We get:   3x + 3y = 17   Divide both sides by 3 to get:x + y = 17/3   So, (x + y)/3 =17/9   Answer: 17/9
<result>C</result>
If 2x + y = 7 and x + 2y = 10, then (x + y)/3 =