scenario 1..
you hit your parlays at 60%..
this means you hit 3 of the 5 parlays...
the parlays require an average of approx. +125 bets to pay out 50 to win 250 (300)
so, you bet 250 (5 x 50) and win 3/5, or 900 total (3 x 300)
That's a profit of 650 dollars.
scenario 2, you win 2 out of 5 .. cashing 600 dollars total (300 x 2)
on 250 bet, so you win 350 dollars.
In both cases you turn a profit. A guaranteed profit.
The only exception would be if 3 of your bets were heavy favorites -1000 and -900 and -500 then 2 of your bets were +20000 and +15000, or something extreme, in which case, there is a possibility that the combinations of the super heavy favorites would not return a profit.
However if you calculate the bets at the average which is about +125, then a profit would be 100% if you go 2/5 or 3/5.
Without knowing the exact
odds of your five bets there is no way to know the exact probability of turning a profit.