The following is a well-known children’s rhyme:
As I was going to St. Ives,
I met a man with seven wives;
Every wife had seven sacks;
Every sack had seven cats;
Every cat had seven kits;
Kits, cats, sacks, and wives,
How many were going to St. Ives?
Assuming that the entire group is actually going to St. Ives,
show that the answer to the question in the rhyme is a partial
sum of a geometric sequence, and find the sum.