Final answer:
To maintain the same ratio as the commercial horsefeed mixture, 1.125 pounds of corn should be mixed with 3 pounds of oats.
Step-by-step explanation:
The question requires us to determine how many pounds of corn should be mixed with 3 pounds of oats based on an existing ratio of 15 pounds of corn to 40 pounds of oats. This is a problem of direct proportion where we can set up a ratio: 15 pounds of corn / 40 pounds of oats = x pounds of corn / 3 pounds of oats. To find x, we cross-multiply and solve for x:
15/40 = x/3
40x = 15 * 3
40x = 45
x = 45 / 40
x = 1.125 pounds
Therefore, 1.125 pounds of corn should be mixed with 3 pounds of oats to maintain the same ratio as the commercial horsefeed mixture.