Question 228561
dear student 
c=25+10x----eq no 1
c=0 +15X----eq no 2
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0=25-5x------eq 1 -eq 2
 5x=25
x=5
put this value into eqn no 1
c=25+10*5
c=75
 please feel free to contact me if you have any doubt 
faithfully
mangesh joshi