Three tuning forks P, Q and R are such that P and Q sounded together give 5 beats per second, Q and R give 9 beats per second, while P and R give 4 beats per second. If the frequency of P is 256 Hz and Q is of higher pitch than P, determine the frequencies of Q and R.
a) Q=251Hz,R=260Hz
b) Q=261Hz,R=260Hz
c) Q=261Hz,R=252Hz
d) Q=261Hz,R=270Hz