Question 1023343
{{{P(X)=C(10,X)*(0.7)^X*(1-0.7)^(10-X)}}}
a) {{{X=8}}}
{{{P(8)=C(10,8)*(0.7)^8*(0.3)^2}}}
{{{P(8)=45*(5764801/100000000)*(9/100)}}}
{{{P(8)=2334744405/10000000000}}}
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b) {{{P=P(8)+P(9)+P(10)}}}
{{{P(9)=C(10,9)*(0.7)^9*(0.3)^1}}}
{{{P(9)=10*(40353607/10000000000)*(3/10)}}}
{{{P(9)=121060821/1000000000}}}
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{{{P(10)=C(10,10)*(0.7)^10*(0.3)^1}}}
{{{P(10)=1*(282475249/10000000000)*1}}}
{{{P(10)=282475249/10000000000
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{{{P=P(8)+P(9)+P(10)}}}
{{{P=478478483/1250000000}}}