Question 87822
s+ns=900 ns=900-s
75s+125ns=95000 now replace ns with (900-s) & solve for s
75s+125(900-s)=95000
75s+112500-125s=95000
-50s=95000-112500
-50s=-17500
s=-17500/-50
s=350 tickes sold to students &
900-350=550 tickets sold to ns. 
proof
75*350+125*550=95000
26250+68750=95000
95000=95000