400 : 1kg
400 : 1000
1 : 2.5 
n = 2.5
        
             
        
        
        
Answer: $75.99
Steps: 149×0.6= 89.4
Multiply 89.4×0.85= 75.99
Hope this helps ʕ•ᴥ•ʔ
        
             
        
        
        
The maximum number of nights he could stay is 4 nights
        
                    
             
        
        
        
Vertex = (6, 5)
axis of symmetry is line x = 6
A third point in the parabola is (12, 0)
equation using the vertex is y = -a(x - 6)^2 + 5 = -a(x^2 - 12x + 36) + 5 = -ax^2 + 12ax - 36a + 5
since the parabola passes through point (0, 0)
i.e. -36a + 5 = 0
a = 5/36 = 0.139
Therefore, the equation is y = -0.139x^2 + 12(0.139)x = -0.139x^2 + 1.667x