hey sorry for that incorrect answer, the approach ofthe problem depends on the choices given and the data given , here the data is temp & pressure, we dont have a direct formula relating rms velocity to pressure & temp , so we need to use our old root (3PV/M)

 

now here temp = 293K (20+273) & pressure = 82m Hg.

 

we know P1V1/T1 = P2V2/T2

 

find volume V2 when P1 = 76 cm of Hg, V1= 22400 cm^3 & T1 = 273 K & P2=82cm of Hg, T2 = 293 K

 

V2 comes out to be = 201.3 * 10^3 cm^3

now

v= root(3P2V2/48)

=396CM/SEC