Quasar

Quasar is a game played in the casino at Flux. It resembles pazaak from Star Wars: Knights of the Old Republic. The player must add random numbers (between certain values) to the score. The object of Quasar is to get the total to twenty, or as close as possible without going over. There are two types of Quasar machine, low and high risk, and appropriate payouts.

Optimal Strategy

Quasar is one of the few games where the casino actually makes a loss if played correctly. The expected return is quite easy to calculate, since there are only three options to choose from every step.

{| class="wikitable toccolours" style="margin: 1em auto 1em auto;" border="1px" cellpadding="10px" cellspacing="0px"

|+ align="top" |Optimal Play
The first column is the current number in play; the second column is the button to press; the third column is the approximate expected high stakes profit, and is an indication of how excited you should currently be. |- style="background-color: #666999;" ! N !! Press !! Likely
Profit !! N !! Press !! Likely
Profit !! N !! Press !! Likely
Profit !! N !! Press !! Likely
Profit |- align="right" | style="background-color: #666999;" | 1 || style="text-align:center;" | 4-7 || 45 | style="background-color: #666999;" | 6 || style="text-align:center;" | 4-7 || 47 | style="background-color: #666999;" | 11 || style="text-align:center;" | 1-8 || 30 | style="background-color: #666999;" | 16 || style="text-align:center;" | 1-8 || -56 |- align="right" | style="background-color: #666999;" | 2 || style="text-align:center;" | 4-7 || 38 | style="background-color: #666999;" | 7 || style="text-align:center;" | 4-7 || 51 | style="background-color: #666999;" | 12 || style="text-align:center;" | 1-8 || 49 | style="background-color: #666999;" | 17 || style="text-align:center;" | Pay Out || 0 |- align="right" | style="background-color: #666999;" | 3 || style="text-align:center;" | 1-8 || 36 | style="background-color: #666999;" | 8 || style="text-align:center;" | 4-7 || 37 | style="background-color: #666999;" | 13 || style="text-align:center;" | 4-7 || 88 | style="background-color: #666999;" | 18 || style="text-align:center;" | Pay Out || 50 |- align="right" | style="background-color: #666999;" | 4 || style="text-align:center;" | 1-8 || 37 | style="background-color: #666999;" | 9 || style="text-align:center;" | 1-8 || 18 | style="background-color: #666999;" | 14 || style="text-align:center;" | 4-7 || 38 | style="background-color: #666999;" | 19 || style="text-align:center;" | Pay Out || 100 |- align="right" | style="background-color: #666999;" | 5 || style="text-align:center;" | 1-8 || 43 | style="background-color: #666999;" | 10 || style="text-align:center;" | 1-8 || 22 | style="background-color: #666999;" | 15 || style="text-align:center;" | 4-7 || -25 | style="background-color: #666999;" | 20 || style="text-align:center;" | Pay Out || 200 |}
Actually, the result for 15 is wrong. You should be using the "1-8" button. Reason: on a result from 1-5, you get either another chance to roll (16), or you get a payoff (17-20). Considering that's 5 out of 8 results, that's a 62.5% chance of getting something useful. The other three outcomes are losses.

The result of "16" is useful, because you have a 50-50 chance of either breaking even (17), or a payoff (18-20).

If you were to choose the "4-7" button, you only get a 50% chance of getting something useful (4, 5), and the other two results are losses.

The decision tree for using "1-8" results in 7 potential loss conditions, and 8 potential win/break-even conditions (getting a 16 doesn't count as a win or a loss), as shown below:

Breakdown:

---

(1) 16 - go to second roll

(2) 17 - break even

(3) 18 - win

(4) 19 - win

(5) 20 - win

(6) 21 - loss

(7) 22 - loss

(8) 23 - loss

(1, 1) 17 - break even

(1, 2) 18 - win

(1, 3) 19 - win

(1, 4) 20 - win

(1, 5) 21 - loss

(1, 6) 22 - loss

(1, 7) 23 - loss

(1, 8) 24 - loss

---

Wins: 6

Break-evens: 2

Losses: 7

You may not win as much, but you will lose less, which gains you more in the end.

Expected Returns

Assuming the automatic first roll when starting a new game of High Stakes Quasar is from the 1-8 button, the average profit per game if you play optimally is 41.81 credits. The following table illustrates the expected return of each action. As you can see, you win about 15-20% of your bet on average.

Expected Return

N	Stop	1-8	4-7	N	Stop	1-8	4-7
1	0.00	238.50	244.61	11	0.00	230.37	192.19
2	0.00	236.40	238.44	12	0.00	249.22	223.44
3	0.00	235.73	232.06	13	0.00	213.28	287.50
4	0.00	237.23	226.87	14	0.00	183.59	237.50
5	0.00	242.82	229.85	15	50.00	161.72	175.00
6	0.00	241.60	247.19	16	100.00	143.75	100.00
7	0.00	232.09	251.15	17	200.00	118.75	0.00
8	0.00	220.39	237.30	18	250.00	87.50	0.00
9	0.00	218.13	210.94	19	300.00	50.00	0.00
10	0.00	221.67	189.06	20	400.00	0.00	0.00

Schells was developing a system to cheat on Quasar by using a device to record wins and losses. His device slightly increased the chance of winning, but got him thrown out for cheating.

Commander Shepard discovered that someone was using a Quasar machine to funnel credits through the system. After Shepard and the squad traced the signal from relay to relay through the Citadel, they found the 'person' responsible was a rogue AI in the back of the Emporium.