Question 953050
Ask yourself:
What is the probability that NONE of the mothers
will choose peanut butter? Call this
probability P(0)
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The probability that AT LEAST ONE mother chooses
peanut butter is whatever probability is left over, or
{{{ 1 - P(0) }}}
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I say that 
{{{ P(0) }}} = ( not PB ) x ( not PB ) x ( not PB ) . . . for all 12 mothers
{{{ P(0) = (1/3)^12 }}}
{{{ P(0) = .000001881 }}}
{{{ 1 - .000001881 = .999998118 }}}
So, the probability is:
.999998118
Definitely get another opinion on this
but I think I'm right