The world's fastest passenger elevator (in the Shanghai Tower in China) travels at 18 m/s. The elevator ride from the 1st floor to the 128th top floor
takes 33 seconds. What is the distance between the 1st floor and the top?

h

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.