a water treatment plant needs to maintain the ph of the water in the reservoir at a certain level. to monitor this, they take 2 oz. of water at 37 locations every hour, measure the ph at each of those locations, and find their average. if the ph level of the reservoir is ok, the results at each location will have varying results, with an average ph of 8.5 and a standard deviation of 0.22. if the ph level of the reservoir is ok, what is the probability that the sample average is less than 8.42?

i believe the answer is three water molecules

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.