<PRE><B>Question 107062</B>
let x= the number of tv advertisements and y = the number of radio advertisements.

x+y=220 .........................1

sincew we know that the tv ads cost $500 and the radio ads $100 the total costs will be given by
500x+100y=30000..................2

we multiply the first equation by 100 and we have

100x+100y=22000..................3

equation 2 - 3

(500x-100x)+(100y-100y)=30000-22000
400x=8000
x=20

x+y=220
20+y=220
y=200

20 tv ads and 200 radio
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