The volume of a medal is 35 cm3 The medal is made from copper and tin.
volume of copper : volume of tin = 21:4
The density of copper is 8.84 g/cm3
The density of tin is 7.38 g/cm3
Work out the mass of the medal.

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.

Find the distance between c and d on the number line c=3 and d=11

Determine the area of a triangle with (see picture below)