[pudley4]

It's just another way of expressing pot odds vs odds of hititng your hand if you only have to call one bet.

Example: You are drawing for a gutshot straight on the turn.

Number of cards left in the deck (D): 46
Number of cards that help you (C): 4
Number of cards that don't help you (D-C): 42
Number of bets in the pot (P): 11

Do you call?

Using the most common method:

Pot odds are (P:1) 11:1 (11 bets in the pot vs the one bet you must call)
Odds of hitting your hand are ((D-C):C) 42:4, or 10.5-1 (number of bad cards vs number of good cards).

Since 11:1 > 10.5:1 you call.

If we take the equation P:1 > (D-C):C, multiply both sides by C, we get P*C > D-C. Then add C to both sides, we get C + P*C > D. Factor out the C on the left side and we get Abdul's equation:

C*(1+P) > D