For L-C-R , AC circuit resonance frequency is 600 Hz and frequency at half power points are 550 Hz and 650 Hz what will be the Q factor?

I know Q factor is (1/Resistance) $\sqrt {\frac {inductance}{capacitance}} $

where is the half power frequency useful then

and also I don't have values of L ,R, C but then how should I proceed the question?