Let +a+ = number of trumpet players
Let +b+ = number of saxophone players
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(1) +a+=+b+-+10+
(2) +b+=+3a+
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Substitute (2) into (1)
(1) +a+=+3a+-+10+
(1) +2a+=+10+
(1) +a+=+5+
and
(2) +b+=+3%2A5+
(2) +b+=+15+
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There are 5 trumpet players
and 15 saxophone players
