<PRE><B>Question 1173094</B>
The mean is the midpoint between the ends or 3.5 min
variance is (b-a)^2/12 or 49/12 or 4.0833 min
sd is sqrt(V)=2.02 min
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wait more than 3 min is (4/7), which may be converted to the decimal.
waiting 1 minute.  The total waiting time must be between 2.1 and 3 minutes. That means the person will wait between 2.1 and 3 minutes 0.9 minute range, with 6 minutes to go, since the clock has started.
That is 0.1500 probability.
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56% wait 3.92 minutes, 7*0.56
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