Oxygen-15 undergoes beta decay. Which particle correctly completes the equation to show that the numbers of nucleons on the two sides of the
equation are equal?
150 - 15N+ ?

Explanation:

Positron emission: In this process, in which a proton inside a radionuclide nucleus is converted into a neutron while releasing a positron and an electron neutrino. The beta positive particle released is basically a positron with +1 charge and no mass.

General representation of an element is given as:  

where,

Z represents Atomic number

A represents Mass number

X and Y represents the symbol of an element

For

no. bullets are macro objects. wave nature is for light waves, extremely tiny particles. if a light particle was the size of your finger, the bullet would be the size of the universe. so basically, that huge difference in size makes the wave nature of matter insignificant.