Question 387941
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Hi,         
Note: The probability of x successes in n trials is: P = nCx* {{{p^x*q^(n-x)}}}
 where p and q are the probabilities of success and failure respectively. 
In this case p =.6 and  q = .4
nCx = {{{n!/(x!(n-x!))}}}
for example:
P(exactly 5 people will make a purchase)= 1287(.6)^5(.4)^8 = .06559

P(less than 8 people make a purchase)  
1- P(8) - P(9) - P(10) - P(11)- P(12) - P(13) = .4256  (Stat Trek)

P(More than 10 people make a purchase) = P(11) +  P(12) + P(13)  
 P(11) +  P(12) + P(13) = .04528 + .01132 + .00131 = .0579