Let T be the temperature at which velocity of sound is 344m/s.
Then the velocity of sound increased from 0°C to T°C would be = 344 - 332= 12m/s
But, given that the velocity of sound increases by 0.6m/s per degree rise in temperature.
Hence, the temperature required to meet the extra velocity 12m/s would be (12/0.6)= 20°C
Thus, the velocity of sound becomes 344m/s when the temperature is 20°C.