Please help solve i dont believe the answer highlighted in gray is correct

22) A 50.0 cm long organ pipe is filled with air at 10.0C and is open at both ends. The speed of sound in air at 0C is 331 m/s. Another 50.0 cm long organ pipe is filled with air at 15.0C and is open at both ends. Wh atis the beat frequency between the fundamental modes of the two organ pipes? 245 Hz 5