Velocity of sound in hydrogen gas at 270C  is  V. Then what is the velocity of sound in helium gas at 1270C  ?

(4)Velocity of sound VS=γRTMNow  for  H2,  γ=5+25=75,  for  He,  γ=3+23=53∴   VHeVH2−δHeδH2  .  MH2MHe .  THeTH2 = 53 .  57  .  400300 .  m2m⇒   VHeV =521 .  23  .  12 =  5257   ⇒   VHe=52 .V37