Solve by completing the square
1 answer:
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Answer:
Step-by-step explanation:
Let X be the random variable for the time needed to grade a randomly chosen first examination paper
X is N(5, 4)
a)
Time taken=11.00-6.50=4hours 10 min=25/6 hours
P(X<25/6) =P(Z<
=0.5-0.0832=0.0168
b) Time >11.10-6.50 = 4 hours 20 mint = 13/3 hours
P(X>13/3) = P(Z>-0.16) = 0.5636