Mr. potter's class will take a test for 1 1/2 hours. they need to finish by 11: 40 to get to lunch on time.
what is the latest time the class can start the test to get to lunch on time?

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