Help I don't think I did it right

The sum of two numbers is 58. the first number is 8 less than half the second number. let  c  represent the first number. let  drepresent the second number. which statements about solving for the two numbers are true? check all that apply. the equation    represents the sum of the two numbers. the equation    represents the sentence “the first number is 8 less than half the second number.”the equation    represents the relationship between the two numbers. the equation    represents the sum of the two numbers. the number  d  is 14.the number  c  is 44.the number  c  is 14.the number  d  is 44.

Which is the correct excel formula for the 80th percentile of a distribution that is n(475, 33)? =norm. dist(80,475,33,1) =norm. inv(0.80,475,33) =norm. s.inv((80-475)/33)?

An automobile assembly line operation has a scheduled mean completion time, μ, of 12 minutes. the standard deviation of completion times is 1.6 minutes. it is claimed that, under new management, the mean completion time has decreased. to test this claim, a random sample of 33 completion times under new management was taken. the sample had a mean of 11.2 minutes. assume that the population is normally distributed. can we support, at the 0.05 level of significance, the claim that the mean completion time has decreased under new management? assume that the standard deviation of completion times has not changed.