16 because 8 rooms have 8-11, 5 rooms have 4-7, and 3 rooms have 0-3 guests.
Gallons of water drank in 4 days = 120
Gallons of water drank in a day = 120/4
= 30
Gallons of water drank in 28 days = 30 × 28
= 840
Let the number be represented by x
2x=60+ 5x -20*2=60+5*-20
2x-5x=5x-5x+60 -40=60+-100
-3x=60 -40=-40
-3x/-3=60/-3
x=-20
Therefore the number is -20
Multiply 18 * 3 and 20 * 3
18*3 = 54
20 * 3 = 60
Length = 54 cm ; Width = 60 cm
Area = L x W
54 * 60 = 3240
Area = 3240 cm