A verbal description of a function is given. Use a formula to express the function. For office supplies you buy s boxes of staples, r reams of paper, and p boxes of ink pens. Staples cost $1.38 per box, paper costs $3.45 per ream, and ink pens cost $2.42 per box. Write a formula that expresses the cost C, in dollars, of all the office supplies as a function of s, r, and p. C =