Question 128642
David's gasoline station offers 4 cents off per gallon if the customer pays in cash and does not use a credit card. Past evidence indicates that 40% of all customers pay in cash. During a one-hour period twenty-five customers buy gasoline at this station. 
(4) What is the probability that at least ten pay in cash? 
A) 0.416 
B) 0.575 
C) 0.586 
D) 0.425 
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That is a binomial problem with n=25,p=0.4,10<=x<=25
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I used the binomcdf function on a TI calculator to get:
1-binomcdf(25,0.4,9) = 0.5754...
Cheers,
Stan H.