Jamaican VS Prostitute

JAMAICAN VS PROSTITUTE 

A jamaican, american and a englishman worked at the same place. after collecting pay a friday evening they were approached by a prostitute saying that they should come see her the next day. when they reach the next day she said 50$ to sex her on the grass, 100$ to sex her on sofa n 150 to sex her on the bed. american went with his 50$ and got it on the grass, english went with 100$  get it on the sofa, jamaican went with 150$ so the prostitute said at last a man of class, the jamaican said "man of which rass class?  3 time pon di grass"