Question 255362
P(speak foreign language) = .20
P(NOT speak foreign language) = .80
(a) What is the probability that none can transact business in a foreign language? 
answer: we want zero "YES" and 10 "NO" so,
nCr*(no)^10*(yes)^0
or
10c0*.8^10*.2^0 ~ .1074
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(b) That at least two can? 
answer: This means that 0 or 1 cannot. It is easier to do this in negation.
1 - p(0 not) + p(1 not) = 1 - 10c0(.8)^0*(.2)^10 + 10c1*(.8)^1*(.2)^9  ~ .99999
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(c) That all 10 can? 
answer; we want all 10 yes, so,
10c10*(.2)^10 ~ 1.02 x 10^-7
(d) Sketch the probability distribution and discuss its appearance. 
The sketch should be a normal curve with cum sum = 1.