Thanks i realised i actually had this test all wrong... so can i for example take a series like

a = 1/ root(3r)

Can i use a p-series like 1/r^(1/3) ie 1/cuberoot(r) (call this b)

which is divergent according to the p-series since p<1.

And then I can deduce that since 0 < b < a and b is divergent, series a is divergent?