Question

Jack and Jill gamble on a roll of a die (yes, a fair die), as follows. If the die shows 1 or 2 spots, Jack gives Jill $1. If the die shows 5 or 6 spots, Jill gives Jack $1. If the die shows 3 or 4 spots, no money changes hands. Suppose Jack and Jill play this game 400 times. The chance that Jill’s net gain is more than $20 is closest to