What's the boiling point water at the top of mt everest (atmospheric pressure =0.54 atm)?

The temperature at which the vapour pressure of substance becomes equal to the atmospheric pressure is called as boiling point.

In this question we are asked about the boiling point of water. We know that water boils at 100 °C when the atmospheric pressure is 1 atm. So, going up to Mount Everest, and boiling water at 0.54 atm means the atmospheric pressure has decreases, so the vapour pressure of water should also have decrease to 0.54 atm and the temperature at which it boils should also decrease.

Result:
          By analyzing vapour pressure at different temperatures it is found that the boiling poimt of water at 0.54 atm pressure is 83.65 °C. I came across this site for finding the exact temperature. (www.endmemo.com/chem/vaporpressurewater.php)