Final answer:
To determine the price Andy paid for a pack of diapers, a system of equations was created from the transactions. After manipulating the equations, it was determined that the price of a pack of diapers was approximately $27.95.
Step-by-step explanation:
To find out how much Andy paid for a pack of diapers, we can set up a system of equations based on the information given. Let's take d to represent the price of a pack of diapers and w to represent the price of a pack of wipes. From the first purchase, we have the equation: 4d + 9w = $219.53. From the second purchase a week later, we have the equation: 1d + 3w = $63.86. To solve for d, we can multiply equation (2) by 4 to make the coefficient of d the same in both equations: 4d + 12w = $255.44. Now we can subtract equation (1) from equation (3) to eliminate d: (4d + 12w) - (4d + 9w) = $255.44 - $219.53, 3w = $35.91. Now we can solve for w: w = $35.91 / 3, w = $11.97 approximately. Now we can substitute the value of w in equation (2) to find d: d + 3($11.97) = $63.86, d + $35.91 = $63.86, d = $63.86 - $35.91, d = $27.95. Therefore, Andy paid approximately $27.95 for a pack of diapers.