Set up an equation and solve for x

Kelly is a salesperson at a shoe store, where she must sell a pre-set number of pairs of shoes each month. at the end of each work day the number of pairs of shoes that she has left to sell that month is given by the equation s=300-15x , where s is the number of pair of shoes kelly still needs to sell and x is the number of days she has worked that month. what is the meaning of the number 300 in this equation

Becca wants to mix fruit juice and soda to make a punch. she can buy fruit juice for $3 a gallon and soda for $4 a gallon. if she wants to make 28 gallons of punch at a cost of $3.25 a gallon, how many gallons of fruit juice and how many gallons of soda should she buy?

Agame has a rectangular board with an area of 44 in2. there is a square hole near the top of the game board in which you must not toss in a bean bag. the square has side lengths of 3 in. what is the probability of not tossing the bag through the hole? a)9/44 b)3/9 c)3/44 d)35/44