What is the solution to this epuation x+6=24

i think the answer is 18 ( please let me know if this answer is wrong ) !

it will cost dollar $540

the living room is 3 which means if we divide 325/3 then we get $108

therefore if 1part of the living room cost $108 and 3 costed $325

then total 5part of the room will cost 5*108 which gives $540