The oral exam will take place at five o´clock p.m. Only Sts with marks minor 5 can t

The oral exam will take place at five o´clock p.m. Only Sts with marks minor 5 can t
 

IS THIS SENTENCE correct ?

The oral exam will take place May 16th at five o´clock p.m. Only Sts with marks minor/under 5 can take it.

The oral exam will take place (on) May 16th at 5:00 p.m. (five o'clock)
Only students with marks under five can take it.

I'll note that we Americans drop the 'th' in "16th" and prefer using digits for the time of day. I also spelled out the abbreviation 'Sts' because it isn't used here (if I guessed correctly).

Instead of 'under', you can substitute 'less than'.