

Choose 1 row from left column, 1 row from right column  
(A1) A sure gain of $240  (B1) A sure loss of $750 
(A2) 25% chance of $1000 gain,
75% gain nothing

(B2) 75% chance to lose $1000,
25% lose nothing

Choose 1 row:
(C1) 25% chance of a $240 gain, 75% chance of $760 loss (C2) 25% chance of a $250 gain, 75% chance of $750 loss 
Maost people choose A1 and B2, which is the same as C1
Choosing A2 and B1 is the same as C2, which is indisputably better
than C1.