80 would be the answer i guess can you explain more in depth?
        
             
        
        
        
Let  be the random variable for the number of marks a given student receives on the exam.
 be the random variable for the number of marks a given student receives on the exam.
10% of students obtain more than 75 marks, so

where  follows a standard normal distribution. The critical value for an upper-tail probability of 10% is
 follows a standard normal distribution. The critical value for an upper-tail probability of 10% is

where  denotes the CDF of
 denotes the CDF of  , and
, and  denotes the inverse CDF. We have
 denotes the inverse CDF. We have

Similarly, because 20% of students obtain less than 40 marks, we have

so that

Then  are such that
 are such that


and we find

 
        
             
        
        
        
Answer:
96 in³
Step-by-step explanation:
Volume = 2(BHD) / 2
The 2s cancel out
Volume = 3(8)4
Volume = 96
 
        
             
        
        
        
Answer:
The answer is true
Step-by-step explanation:
To find the area of a trapezoid, multiply the sum of the bases (the parallel sides) by the height (the perpendicular distance between the bases), and then divide by 2