As a youngster, I bought more music on cassette than any other format. (A brilliant decision in retrospect, considering that it's probably the least-collectible recording format ever offered.) But I did own a handful of music albums (most won from contests on local radio stations) and a few singles, as well. Speaking of those 45s:

How many grooves are on a
standard 7" diameter 45RPM record
whose A-side is 4:20 long and
whose B-side is 3:45 long?

Here is the ANSWER.

THE ANSWER:

TWO; one on each side.

Neither the length of a record nor its playing speed has any effect on the number of grooves. With rare exception, vinyl records have one groove per side.