Jack says, "there is no rational number between 1 7 and 1 8 ." mary replies, "yes there is, because 2 15 is between them." is mary right? a) no, because the denominators are different. b) no, since there 2 is larger than 1 and 15 is larger than 7 or 8. c) yes, because 1 7 + 1 8 = 2 15 , which is between them. d) yes, since 1 7 = 0.143, 1 8 = 0.125, and 2 15 = 0.133.