The concentration of particles in a suspension is 50 per mL. A 5 mL volume of the suspension is withdrawn.

a. What is the probability that the number of particles withdrawn will be between 235 and 265?
b. What is the probability that the average number of particles per mL in the withdrawn sample is between 48 and 52?
c. If a 10 mL sample is withdrawn, what is the probability that the average number per mL of particles in the withdrawn sample is between 48 and 52?
d. How large a sample must be withdrawn so that the average number of particles per mL in the sample is between 48 and 52 with probability 95%?


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