Use permutations to solve. In a club with 23 members, how many ways can the club elect a president and a treasurer? . . . Substitute values into the formula for Pr. n There are different ways that the offices can be filled.A shipment contains 12 igneous, 10 sedimentary, and 10 metamorphic rocks. If 4 rocks are selected at random, find the probability that exactly 2 are sedimentary. _ -5 The probability that exactly 2 of the rocks are sedimentary is D (Round to four decimal places as needed.)