A full 5-ary tree with 37 internal nodes has 381 nodes in total.
How to solve
In a full 5-ary tree, each internal node has 5 children. Let's denote the number of levels in the tree as h.
At each level, the number of nodes is given by the formula

If we have 37 internal nodes, then the total number of nodes in the tree can be expressed as:
Total nodes =

We know that there are 37 internal nodes, so we can set up an equation:
37 =

Solving for h, we get:
h = 4
Now that we know the height of the tree, we can calculate the total number of nodes:
Total nodes =

Therefore, a full 5-ary tree with 37 internal nodes has 381 nodes in total.