Probability question gah!!!?

Question

A saleswoman normally visits 60 homes in a week. She has a 20% chance of making a sale (indepent events)

If the woman was to only visit 12 homes, what is the probability of her making more than 6 sales?

Answer 1

60 * (0∙2) = 12 sales.
12 * (0∙2) = 2∙4 sales.
2∙4/ 6 = 0∙4% Probability.

Answer 2

0.2^7*12! / ( 7! * (12-7)! )

plus same thing with 7 replaced by 8,9,10,11,12

n! = 1*2*3*...*n
1!=0!=1

Answer 3

Use binomial distribution,
(0.2 + 0.8)^12

Here is the answer:
∑C(12, i)(0.2^i)[0.8^(12-i)], i from 7 to 12.

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intel_kni,

You need to consider 0.8^(12-i) for unsuccessful sales.