320/(b*8-40)=10 (n/4-35)*6=150
320/(b*8-40)=10 8b-40=320/10 8b-40=32 8b=32+40 8b=72 b=72/8 b=9 (n/4-35)*6=150 n/4-35=150/6 n/4-35=25 n/4=25+35 n/4=60 n=60*4 n=240