SOLUTION: A ROOM MEASURES 3M BY 4M BY 7M. THE WALLS NEED 2 COATS OF PAINT. A 4-L CAN OF PAINT COVERS 40M SQUARED. HOW MUCH PAINT SHOULD TANYA BUY? I KNOW THE ANSWER BUT NOT HOW I GOT IT.

Question 34293: A ROOM MEASURES 3M BY 4M BY 7M.
THE WALLS NEED 2 COATS OF PAINT. A 4-L CAN OF PAINT COVERS 40M SQUARED.
HOW MUCH PAINT SHOULD TANYA BUY?
I KNOW THE ANSWER BUT NOT HOW I GOT IT.
Answer by benni1013(206) (Show Source): You can put this solution on YOUR website!
When doing surface area find all the possible combination of the numbers and multiply it by two.
(3*4)+(3*7)+(7*4)=61*2=122 meters^2
This is your surface area for the room.
122/40=3 and a little so you need 4 but you need two coats so you need 7. The decimal when you originally divide is so negligible that you won't need 8 cans.
This tells you how many cans of paint she needs to buy.
7*4=28 liters of paint. 7 equals the number of cans to buy 4 equals the amount in each can.
RELATED QUESTIONS
A room measures 4m by 7m and the ceiling is 3m high. A liter of paint covers 20m^2. How... (answered by josmiceli)

A room is 3m high and it's floor is rectangle of 5m by 4m . 1L of paint covers 12msq. How (answered by ikleyn)

a gallon of paint covers 500^2ft. how many gallons of paint are needed to apply two coats (answered by checkley77)

You want to paint the walls and ceiling of a room that measures 3mx4m and is 2.7m high .... (answered by Boreal)

Sergio plans to paint the 4 walls of his room with 1 coat of paint. The walls are... (answered by Theo)

Determine the number of cans of paint needed to paint three rooms of a house (walls and... (answered by josgarithmetic,josmiceli)

Ashley is painting a room. The room consists of four walls measuring 22 feet in length... (answered by ohtheirony)

Jacqueline is painting a room, and she needs to know how much paint to buy. The room is... (answered by stanbon,josmiceli)

Two painters josh and Bose can paint the four walls of a room together in 6 hours whose... (answered by Theo)