Question 374806
For 1 pair, it's {{{P[1]=3.50}}}
For 1 pair of the 6 pack it's, {{{P[6]=19.50/6=3.25}}}
{{{((P[6]-P[1])/P[6])*100=((3.25-3.50)/(3.25))*100=-0.07692*100=-7.7}}}% 
It's 7.7% cheaper.