Need some help with a gambling, math problem

In order to be a profitable sports bettor, i know you need to win approx. 52.5% of your bets. I did very well this NFL season and won 56.8% of my bets. 

If I'm looking at this right, you still need 52.5% (roughly) to make a profit. Getting 20% back on your losses still makes it a loss, just less painful.

Let's say you bet 100 games to win $100 each and go 50-50 at -110 odds. You win $5000 and lose $5500 for a total loss of $500. Getting 20% back is $100, so a net loss of $400. A losing week is still a losing week. At 52% you win 5200 lose 5280 = $80 loss, less 20% back is a loss of $64.

No matter how you look at it, you still need that 52.5% to have a profitable week, but if someone is willing to cut your loss in any given week by 20% I don't see a downside.

Thanks bruin and danrules, i was going to do the same math this morning that danrules did however it does seem you made a small mistake, which bruin was keen enough to catch. Wow though 47% sounds like a dream come true, if i could recreate last years success i'll be  a very happy man. 

Ace, do you get 20% back on each individual game you lose or do you get back 20% of your total losses for the week in which you ended up down for the week? 

End of the week totals. If i lose $1000 at the end of the week, i get 20% back, $200. If i win, i just get my profits. 

If that is the case, then my math in post 2 is correct, not what Bruin posted in #3.

basically he is offering you -108 odds. 

yes it's simple good business but you still are losing money bottom line.

would enoy getting 20% cut off losses

so i went 1- 3 one week $100 wagers i would lose $230 cut 20% is $46 less so i only pay out $184

i think this clears up the math problem ACE

Bookies never lose If i booked i would give back 40% and still make nice profits

heres the example 10 people lose $11000 

thats $1100 each so X 40% is $440 off I'm still making obscene profits $6600 for the week thats on the 10 losers now if i have 20 winners i'm still losing because winners were more than losers

but i guees just giving that reduction to 1 or 2 players ain't going to drive any bookie broke.

I want to start my own book here min wager $5 but all cash up front with receipts for each player

Thanks for all the help guys. The 20% only kicks in on losing weeks so it's tough to figure out exacly what my advantage is. It's nice to get a little something back after a potential tough week.