Mark can clean his father's office in 30 minutes. his younger sister lynn can clean the office in 40 minutes. how long will it take if they come together and clean the office

An assembly consists of two mechanical components. suppose that the probabilities that the first and second components meet specifications are 0.87 and 0.84. assume that the components are independent. determine the probability mass function of the number of components in the assembly that meet specifications. x

Ill mark the brainliest if you me with the these three questions 7,8,9

Pls brainliest will be awarded if answer is correct