THE GROOVY CONUNDRUM

Showing my age with this one. An old gramophone record spins round 78 times per minute. It lasts for 4 minutes. How many grooves does it have?

--------------------------------- ----------------------------------

Scroll down for the answer

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

One. Which goes all the way round.

--------------------------------- ----------------------------------