Could someone correct this for me? I was told it’s wrong

Abag contains 3 red marbles 4 white marbles and 5 blue marbles if one marble is drawn from the bag what is the probability that the marble will be blue

Boris needs to buy plastic spoons. brand a has a box 42 spoons for $2.37. brand b has a box of 72 spoons for $3.57. find the unit price for each brand. then state which brand is the better buy based on the unit price. round your answer to the nearest cent.

3x = 729 solve for x plz . it's urgent. will mark