Two identical flutes produce fundamental notes of frequency 300 Hz at 270C . If the temp of the air in one flute is increased to 310C.  The number of beats heard per second will be

V2V1=273+31273+271/2=3043001/2=(152150)1/2  We know,  frequency is proportional to speed of sound ∴n2n1=V2V1=1+21501/2 ≃1+1150 use binomial approx⇒n2= 300×1+1150=300+2=302 Hz∴beat frequency =302−300=2 Hz