The 1st, 4th and 8th terms of an arithmetic sequence, with common difference d, d ≠ 0 , are the first three terms of a geometric sequence, with common ratio r. Given that the 1st term of both sequences is 9 find the value of d and the value of r

Mariah is randomly choosing three books to read from the following: 5 mysteries, 7 biographies, and 8 science fiction novels. which of these statements are true? check all that apply. there are 20c3 possible ways to choose three books to read. there are 5c3 possible ways to choose three mysteries to read. there are 15c3 possible ways to choose three books that are not all mysteries. the probability that mariah will choose 3 mysteries can be expressed as . the probability that mariah will not choose all mysteries can be expressed as 1 −