Answer:
a.0.0199 
b.0.1765 
c.0.0785 
d.0.1268 
e.Yes
Explanation:
It is given that   X follows a  Binomial distribution with (n= 500, p = 0.05)
The  probabilities  are computed using the EXCEL .
a) The required probability here is:
P(X less of equal to  15)
= binom.dist(15,500,0.05,TRUE)
=0.0199 
Therefore the probability is 0.0199 .
b) The required probability here is:
P(X greater or equal to 30) = 1 - P(X less or equal to  29)  
=1 - binom.dist(29,500,0.05,TRUE)
=0.1765 
Therefore the probability is 0.1765 
c) P(X = 26 )
= binom.dist(26,500,0.05,FALSE)  
=0.0785 
Therefore the probability is 0.0785 
d) The required probability here is computed as:
P(10 less or equal to X less or equal to 20 ) = P(X less or equal to 19) - P(X less or equal to 10)
= binom.dist(19,500,0.05,TRUE) - binom.dist(10,500,0.05,TRUE)
=0.1268 
Therefore the probability 0.1268 
e) Yes . Therefore the probability because that is the assumption used to apply binomial distribution .