Which expression is equivalent to 3(6m) + m? 19m? 21m? 7m+3? or 18m +6m^

i dont get it. where are the "descriptions"?

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