Question

What happening to the remaining of sperm when ONE sperm enters into the egg ?

Answer 1

In a single ejaculation about 200 million sperms enter vagina. Your question is that only a single sperm reaches egg and where other sperms go?
Rest of the sperms are killed by acidic fluids present inside vagina.
Some are trapped inside mucus.
Some are attacked by white blood cells.

Here is answer to ur question..