Question 970661
In a basketball free-throw contest, the probability that Eric will be successful on each shot is 4/5. Find the Probability that Eric will be successful in:
a)exactly 2 out of 3 shots
probability = {{{(matrix(2,1,3,2))(4/5)^2(1/5)}}} = {{{highlight(0.384)}}}

b)at least 2 out of 3 shots
probability = {{{(matrix(2,1,3,2))(4/5)^2(1/5) + (matrix(2,1,3,3))(4/5)^3(1/5)^0}}} =  {{{highlight(0.896)}}}
c)at most 1 out of 3 shots
probability = {{{(matrix(2,1,3,0))(4/5)^0(1/5)^3 + (matrix(2,1,3,1))(4/5)^1(1/5)^2}}} =  {{{highlight(0.104)}}}
d)exactly 2 out of 4 shots
probability = {{{(matrix(2,1,4,2))(4/5)^2(1/5)^2}}} = {{{highlight(0.1536)}}}