Pollsters are concerned about declining levels of cooperation among persons contacted in surveys. a pollster contacts 77 people in the 18-21 age bracket and finds that 65 of them respond and 12 refuse to respond. when 301 people in the 22-29 age bracket are contacted, 275 respond and 26 refuse to respond. assume that 1 of the 378 people is randomly selected. find the probability of getting someone in the 18-21 age bracket or someone who agreed to respond.

0.272

Step-by-step explanation:

Given:

Age group         Number of people        Respond          Refused to respond

18-21                             77                             65                              12

22-29                         301                             275                            26                          

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Total                         378                              340                            38

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Now,

P (the probability of getting someone in the 18-21 age bracket or someone who agreed to respond)

= P ( 18-21 ) + P ( Refused to respond ) - P ( 18-21 and refused to respond)                      

=  + -

=

=

= 0.272

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