given the scale is : 1 inch = 3.5 feet
The width = 3 inches , so, the actual width = 3 * 3.5 = 10.5 feet
The length = 4 inches , so, the actual length = 4 * 3.5 = 14 feet
so, the area of the actual bedroom = length x width = 14 * 10.5 = 147 square feet