1. A hotel has 300 rooms which are all occupied. Each room can have either 1 or 2 guests and there are 420 guests staying in total. How many rooms are occupied by 2 guests?

60

Step-by-step explanation:

420 - 300 = 120

120/2 = 60

answer: 204

step-by-step explanation:

we are told that the revenue is

x⋅(4080−10x)=−10x^2+4080x

this is a quadratic function, so to maximize it we should find the x-value of its vertex. recall that the x-value of the vertex of the parabola ax^2+bx+c is given by the formula −b/2a.

so in this case, we have a=−10 and b=4080, so the x-value of the vertex is

−b/2a= −(4080)/2(−10)=204