concert tickets In $400,$200 and $100 each are available for sale.the number of $200 tickets sold is a 4 times as many as that of $400 tickets.the number of $100 tickets sold is 380 more than that of $200 tickets.if the total income from te sale of tickets is $86000,how many $400 tickets are sold?
问题描述：
concert tickets In $400,$200 and $100 each are available for sale.the number of $200 tickets sold is a 4 times as many as that of $400 tickets.the number of $100 tickets sold is 380 more than that of $200 tickets.if the total income from te sale of tickets is $86000,how many $400 tickets are sold?
答
设200$票为X,有100*（X+380）+200X+400*0.25X=86000.X=120.100$的500张,200$的120张,400$30张.