Three-Card Bounty

 is a quest in Fallout: New Vegas.

Quick walkthrough
Violet, Cook-Cook, and Driver Nephi have been giving Major Dhatri a major problem and he wants their heads on a plate.

Detailed walkthrough
Cook-Cook

Cook-Cook is easily the closest of the bounties to the airport. To avoid a few unnecessary Fiends you must travel north along the highway near the airport until you reach a few frag mines. Take a left turn towards Vault 3 and you should notice a large group of Fiends (5 to 8). Cook-Cook is one of them. He has an incinerator he'll use for long range attacks and a flamer for closer ranges, provided he gets an opportunity to fight back.

There are several ways to approach the situation:

1)Killing Queenie.
 * If you talk to Little Buster before setting out after Cook-Cook, you can learn that Cook-Cook has a favorite brahmin named Queenie, and that killing Queenie would incite Cook-Cook to fly into a rage, attacking anyone near him, including Fiends. Shooting Queenie from a distance (from the northwest of the ruins should be easiest) and waiting for the fighting to end is one option: sometimes the Fiends kill Cook-Cook, sometimes he kills the Fiends, but either way, the survivor(s) should be easy to handle.

2)Sniper solution.
 * The simplest approach is probably just to shoot Cook-Cook with a scoped rifle. Because he wears metal armor, you should use armor piercing rounds.  With a good scoped rifle (Ratslayer, Scoped hunting rifle, Sniper rifle, Anti-materiel rifle) and appropriate ammunition, you should be able to kill him with one or two shots to the chest, allowing you to collect the full bounty.

3)Charging in.
 * If you prefer short range or melee combat, you can always just rush in. You'll face about half a dozen fiends, and Cook-Cook, who is easily the most dangerous. As such, a good strategy is to shoot the incinerator out of his hands, and walk backwards while shooting as he tries to get into flamer range. He wears metal armor, so armor piercing bullets are recommended. Also remember to avoid shooting him the head, else your pay will suffer.

For an extra reward, talk to 1st Recon Sniper Corporal Betsy after killing Cook-Cook, and she'll give you 360 NCR dollars. Pretty Sarah in Westside will also reward you upon hearing you have performed this "service to humanity."

Violet

Violet has no other Fiends to support her, but does have a pack of dogs. Located just to the west of Cook-Cook's location, you will be confronted with approximately 6 Dogs, 1 of which is Unique - Violetta - who takes slightly more to kill than the other dogs. Violet herself is relatively easy to kill as she doesn't wear specifically tough armor, and only uses a Hunting Rifle.
 * If you have Level 2 of the Animal Friend perk, all of Violet's dogs become friendly to you.

Driver Nephi

Driver Nephi is the furthest away of the three, however, he is much easier to take care of than Cook-Cook. You are given the option to assemble First Recon at the Samson Rock Crushing Plant, which is just outside where Driver Nephi is situated. He is surrounded by approximately 5 other Fiends. Driver Nephi himself is very easy. He only uses a melee weapon, his golf club - Nephi's Golf Driver - which, whilst powerful, is simple to fight against (by not letting him get into melee range). Either shoot him from long range, or lure him to the trap set by 1st Recon at Samson Rock Crushing Plant.
 * Letting the 1st Recon squad kill him allows an additional 300 cap reward.
 * Note that if you follow First Recon to the rock plant on foot, instead of fast traveling after speaking with Lieutenant Gorobets, they will encounter a minefield as they cross a road directly east of the rock crushing plant, in line with The Basincreek Building, so it may be worth clearing these mines beforehand.

Returning to Dhatri will give you 250 caps per bounty (50 caps if the head is mangled) and 100xp per bounty.

Bugs
[Happened in Game version: 1.1.1.271] In the PC game, after killing Driver Nephi and returning the head to Major Dhatri and choosing the option to reclame your bounty, Dharti may ask to see the head but nothing happens and the conversation ends, you must keep talking to him until the head is removed from your inventory and your bounty recieved, this may take several attempts.

Behind the scenes
The title of this quest is a play on the name of the confidence game, Three-card Monte.