Question

Suppose that in an assortment of 25 calculators there are 5 with defective switches. Draw with and without replacement. (Enter the probabilities as fractions.)

(a) If one machine is selected at random, what is the probability it has a defective switch? with replacement _____ without replacement ____

(b) If two machines are selected at random, what is the probability that both have defective switches? with replacement ___ without replacement ____

(c) If three machines are selected at random, what is the probability that all three have defective switches? with replacement ___ without replacement ____

Assume a jar has four red marbles and three black marbles. Draw out two marbles with and without replacement. Find the requested probabilities. (Enter the probabilities as fractions.)

(a)    P(two red marbles)

with replacement
without replacement

(b)    P(two black marbles)

with replacement
without replacement

(c)    P(one red and one black marble)

with replacement
without replacement

(d)    P(red on the first draw and black on the second draw)

with replacement
without replacement

Answer 1