Detailed Instructions: In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.
Q: Problem: the cost of carpeting a room 18 m long with a carpet 75 cm wide at 4.50 per metre is 810 . the breadth of the room is :
Options: a ) 7 m , b ) 7.5 m , c ) 8 m , d ) 8.5 m , e ) none of these
A:
b