The dimensions of the room is not given. Lets assume a value and calculate BTU accordingly.
Answer and Explanation:
BTU, or British Thermal Unit, is defined as the amount of heat required to raise the temperature of 1 pound of water by 1° F.
In other words,BTU's measures the amount of heat an AC (or any other cooling unit) can remove from a room per hour. Higher the BTU, the more powerful the cooling.
Calculation:
Lets assume that a room is 10 feet wide and 14 feet long.
Calculate the size of the room by multiplying the height of the room with its width:
size of the room= 10 × 14
= 140 square feet
Then multiply the size of the room that you obtained in step 1 with 20 BTU per square foot, in order to get the minimum BTU's required for AC to cool a room,
140 × 20= 2800
2800 BTU cooling capacity is required.