I need to understand question 14 and 15 and the last one cut off for tens in one

                                                 Question # 14

Given the numbers

10     11     12     13     14     15     16     17     18     19     20

Let 'x' be the number

The condition breakdown:

I am less than 20.

I am more than 13.

I am less than 17.

Finally:

I am 4 more than 12

i.e. 12+4 = 16

Thus, the number is x = 16

                                               Question # 15

Part a)

Given the numbers

10     11     12     13     14     15     16     17     18     19     20

Let 'x' be the number

The condition breakdown:

I am more than 10.

I am less than 20.

I am more than 12.

I am less than 15.

As the numbers left after all the conditions are fulfilled are 13 and 14.

So, from the remaining number 13 and 14;

14 > 13

Thus, the number x = 14

Part b)

Drawing the number 14 in the place value:

          Chart

Tens                Ones

1                         4

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