SOLUTION: Please help me create and linear system and solve for this word problem. 45 high school students and adults were surveyed about their use of the internet. 31 people reported a

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Question 938319: Please help me create and linear system and solve for this word problem.
45 high school students and adults were surveyed about their use of the internet. 31 people reported a heavy use of the internet. This was 80% of the high school students and 60% of the adults. How many students and how many adults were in the study?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +a+ = number of adults surveyed
Let +b+ = number of HS students surveyed
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(1) +a+%2B+b+=+45+
(2) +.6a+%2B+.8b+=+31+
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(2) +6a+%2B+8b+=+310+
Multiply both sides of (1) by +6+
and subtract (1) from (2)
(2) +6a+%2B+8b+=+310+
(1) +-6a+-+6b+=+-270+
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+2b+=+40+
+b+=+20+
and
(1) +a+%2B+20+=+45+
(1) +a+=+25+
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There were 25 adults and 20 students in the study