Question

Most evenings after dinner Duarte spends 30 minutes playing chess with his dad.

Answer 1

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!  :)