For a heap node with an index of 3 and a parent index of 1, the child node indices can be calculated using the following formula:
Left Child Index = (2 * Parent Index) + 1
Right Child Index = (2 * Parent Index) + 2
Using these formulas, we can find the child node indices for the given parent index:
Left Child Index = (2 * 1) + 1 = 3
Right Child Index = (2 * 1) + 2 = 4
Therefore, the child node indices for the given parent index of 1 are 3 and 4.
As for the new array created after the add operation to create a max-heap, the given array is: 47 25 36 60 54.
To create a max-heap, we need to ensure that every parent node is greater than or equal to its child nodes. If the add operation involves adding a new element to the heap, we would need to perform the necessary adjustments to maintain the max-heap property.