SOLUTION: In a rec year, companies spent a total of $86.9 Billion on Newspaper, television and radio ads. The total amount spent on Tv and Radio ads was only $2.7 Billion more than the amoun

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Question 839154: In a rec year, companies spent a total of $86.9 Billion on Newspaper, television and radio ads. The total amount spent on Tv and Radio ads was only $2.7 Billion more than the amount spent on newspaper ads alone. The amount spent on newspaper ads was $5.5 Billions more than what was spent on Tv ads. How much was spent on each form of advertising ? please help I am so lost on this one
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +a+ = amount in billions spent on newspaper ads
Let +b+ = amount in billions spent on TV ads
Let +c+ = amount in billions spent on radio ads
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(1) +a+%2B+b+%2B+c+=+86.9+
(2) +b+%2B+c+=+a+%2B+2.7+
(3) +a+=+b+%2B+5.5+
----------------------
There are 3 unknowns and 3 equations
so it is solvable
Substitute (2) into (1)
(1) +a+%2B+a+%2B+2.7+=+86.9+
(1) +2a+=+86.9+-+2.7+
(1) +2a+=+84.2+
(1) +a+=+42.1+
and
(3) +42.1+=+b+%2B+5.5+
(3) +b+=+42.1+-+5.5+
(3) +b+=+36.6+
and
(1) +42.1+%2B+36.6+%2B+c+=+86.9+
(1) +c+=+86.9+-+78.7+
(1) +c+=+8.2+
-------------------------
42.1 billion was spent on newspaper ads
36.6 billion was spent on TV ads
8.2 billion was spent on radio ads
check:
(2) +b+%2B+c+=+a+%2B+2.7+
(2) +36.6+%2B+8.2+=+42.1+%2B+2.7+
(2) +44.8+=+44.8+
OK -you can check the other 2 equations