Using feet or centimeters when measuring length is an example of ?

In parallelogram abcd the ratio of ab to bcis 5: 3. if the perimeter of abcd is 32 find ab

The total number of dental clinics total for the last 12 months was recorded

There are three bags: a (contains 2 white and 4 red balls), b (8 white, 4 red) and c (1 white 3 red). you select one ball at random from each bag, observe that exactly two are white, but forget which ball came from which bag. what is the probability that you selected a white ball from bag a?