3. y=x*25, y is the number of pages read and x is the time used to read them in hours.
4. y= 40*x, y is the number of miles run and x is the time in hours.
5. y=3*x so k=3, y is the total number of pens, x is the number of boxes, and k is the number of pens per box.
6. y=6*x so k =6, y is the number of muffins, x is the number of packs, and k is the number of muffins per pack.