The total amount of money collected from the boy's payment is 40*$50 = $<<40*50=2000>>2000
There are four times as many boys at Lulu's party as girls, meaning there are 40/4 = <<40/4=10>>10 girls at the party.
since each boy paid twice the money that each girl paid to attend the party, each girl paid $50/2 = $<<50/2=25>>25
The total amount of money collected from the girl's payment is $25*10 = $<<25*10=250>>250
The total amount of money collected at the party is $250+$2000 = $<<250+2000=2250>>2250
#### 2250