The difference of 3 times a number and 16 is at least 8.

T= total played
e= # evenings played
m= # minutes played

Total equals number of evenings played multiplied by number of minutes plated per evening.

EQUATION:
t=e * m

EQUATION (if 30 minutes per evening):
t=30e

Example:
3 nights, 30 minutes played

t= 3 * 30
t=90 minutes total played

Hope this helps!  :)