Answer: 0.8015
Step-by-step explanation:
Let F= event that a person has flu
H= event that person has a high temperature.
As per given,
P(F) =0.35
Then P(F')= 1- 0.35= 0.65               [Total probability= 1]
P(H | F) = 0.90
P(H|F') = 0.12
By Bayes theorem, we have

Required probability = 0.8015
 
        
             
        
        
        
The area of the square: 

where "a" is a length of side.
Therefore:
 
 
        
        
        
X+7<23
x<23-7
x<16
So, all numbers from zero to 15
Those are 16 positive integers