Question

Someone please help me please please please

Answer 1

1) A={3,5,7,9,11}            B={4,8,12},  and  A∪B ={3,4,7,8,9,11,12}

2) Normal distribution with Mean 80% & SD = 5%
The here below "distribution" is easy to figure out
                       

            --70%----------75%------------ 80%--------85%-----90%------
              -2σ            -1σ                   Mean         1σ          2σ
You should know for + or - 2σ the probability is 95%. Since here we are taking half of it will be 47.5%

For the last one I don't have the Z-Score Table. Sorry