A cleaning company charges x dollars per hour to clean floors and y dollars per hour to clean the rest of the house -when the company spends 2 hours to clean floors and 3 hours to clean the rest of a house, the total is $84.
-when the company spends 1 hour to clean floors and 4 hours to clean the rest of a house, the total is $87

Which ordered pair represents the hourly charges to clean floor and to clean the rest of the house?

A.(12,20)
B.(15,18)
C.(20,12)
D.(18,15)