What does the notation Rx-axis(DAB) mean?

Ngrid mixes 3.6 pounds of almonds with some raisins to make a trail mix. she divides the trail mix into 12 equal portions. each portion weighs 0.7 pound. how many pounds of raisins did she use to make the trail mix? express the answer to the nearest tenth.

What is the size of the matrix resulting from

Monthly water bills for a city have a mean of $108.43 and a standard deviation of $32.09. find the probability that a randomly selected bill will have an amount greater than $155, which the city believes might indicate that someone is wasting water. would a bill that size be considered unusual?