Tracy, joyce, mark and sarah collect key chains. they have an average of 68 keychains. joyce has half as many as mark. sarah has 28 fewer than the total number of keychains that joyce and mark have. how many keychains does mark have?

Fred has a total of 62 dvd and cd. if the number of cd is three more than two times the number of dvd, how many cd does he have?

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

The angles in a triangle are represented by 5x, 8x, and 2x+9. what is the value of ? a.10.8 b.11.4 c.9.7 d.7.2