Paul has 2/3 as many postcards as shawn . the number of postcards shawn has is 3/5 of the number of postcards tim has. if the three boys have 280 postcards altogether, how many more postcards does tim have than paul ?

Suppose the first five terms of a sequence are 4, 5, 9, 27, 123. how could the next term in the sequence be generated?

Measures of the angle of r, 31 s (x+4) t (3x+9)

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.