Note: I'm not sure what do you mean by "weight 0.05 kg/L". I assume it means the mass per unit of length, so it should be "0.05 kg/m".
Solution:
The fundamental frequency in a standing wave is given by

where L is the length of the string, T the tension and m its mass. If we plug the data of the problem into the equation, we find

The wavelength of the standing wave is instead twice the length of the string:

So the speed of the wave is

And the time the pulse takes to reach the shop is the distance covered divided by the speed:
Answer:
Sorry I'm wrong The person above is correct.
I tried.
Answer:
2452.79432 m/s
Explanation:
m = Mass of ice
= Latent heat of steam
= Specific heat of water
= Latent heat of ice
v = Velocity of ice
= Change in temperature
Amount of heat required for steam

Heat released from water at 100 °C

Heat released from water at 0 °C

Total heat released is

The kinetic energy of the bullet will balance the heat

The velocity of the ice would be 2452.79432 m/s