If you're fire or water that's easy to pass.

There is a few tricks to do.

Round 1
1. Stop Hashirama with cc (Acupuncture, Sleep, Chaos)
2. Stop Minato with standard and cc him. Make sure you can make a combo with that standard.

If Minato dodges, start again.

Round 2
1. Stop Minato with CC

If Minato dodges you lose, start again.

Round 3
1. Stop Tobirama

Then the rest should be easy to kill Hashirama and Saru

Took me about 2-3 tries.

Go to the strategy section and look for the exam 100 build for water. Switch to water for a day and go beat the exam; you will have a much easier time than any other main.

Thank you very much boys!

also forgot to mention Tobirama's blind.

Round 1

if he blinds your initiator who can attack to create combo, start again. Cos Minato will kill you all.

So round 1 is depending on your luck on 2nd's blind and 4th's dodge.

I need to have the high refinement to pass the 100 exam?

nope. just make sure minato doesn't dodge that should be free win.