Respuesta :

13. x + y = 40
     2.25x +1.75y = 83.50

Multiply the first equation by -2.25
So you get -2.25x + -2.25y = -90

So now your equations are -2.25x + -2.25y = -90
                                              2.25x +1.75y = 83.50
And add them together      -------------------------------
                                                          -.5y = -6.5
                                                        ÷-.5     ÷-.5
                                                   ------------------------
                                                             y = 13
Now that you know y= 13 then u can plug it into any of the equations
i use x + y = 40 since it's easier
So plug in 13 for y
You should get x + 13 = 40
                             -13     -13
                        ---------------------
                                 x = 27

So 27 hotdogs and 13 popcorns were purchased.
Q&A Education