Aurevia, Brelosia, Cyrenia and Zerathania are four countries with their currencies being Aurels, Brins, Crowns, and Zentars, respectively. The currencies have different exchange values. Crown's currency exchange rate with Zentars = 0.5, i.e., 1 Crown is worth 0.5 Zentars.

Three travelers, Jano, Kira, and Lian set out from Zerathania visiting exactly two of the countries. Each country is visited by exactly two travelers. Each traveler has a unique Flight Cost, which represents the total cost of airfare in traveling to both the countries and back to Zerathania. The Flight Cost of Jano was 4000 Zentars, while that of the other two travelers were 5000 and 6000 Zentars, not necessarily in that order. When visiting a country, a traveler spent either 1000, 2000 or 3000 in the country's local currency. Each traveler had different spends (in the country's local currency) in the two countries he/she visited. Across all the visits, there were exactly two spends of 1000 and exactly one spend of 3000 (in the country's local currency).

The total “Travel Cost” for a traveler is the sum of his/her Flight Cost and the money spent in the countries visited.

The citizens of the four countries with knowledge of these travels made a few observations, with spends measured in their respective local currencies:

i. Aurevia citizen: Jano and Kira visited our country, and their Travel Costs were 3500 and 8000, respectively.

ii. Brelosia citizen: Kira and Lian visited our country, spending 2000 and 3000, respectively. Kira's Travel Cost was 4000.

iii. Cyrenia citizen: Lian visited our country and her Travel Cost was 36000.

What was Jano's total spend in the two countries he visited, in Aurels?

The correct answer is 1500.

Let us begin by identifying the two countries each traveler visited based on the given observations. We know there are four countries: Aurevia (Aurels, A), Brelosia (Brins, B), Cyrenia (Crowns, C), and Zerathania (Zentars, Z). The travelers Jano, Kira, and Lian set out from Zerathania to visit exactly two of the other three countries (A, B, C). We are told that each country is visited by exactly two travelers, making a total of 6 visits (2 visits per country).

From the observations:
- The Aurevian citizen notes that Jano and Kira visited Aurevia.
- The Brelosian citizen notes that Kira and Lian visited Brelosia.
- Since each country is visited by exactly two travelers, the remaining country, Cyrenia, must have been visited by Jano and Lian.
Thus, the visits are as follows:
- Jano visited Aurevia and Cyrenia.
- Kira visited Aurevia and Brelosia.
- Lian visited Brelosia and Cyrenia.

Next, we analyze the local currency spends. There are 6 visits in total. The travelers spent exactly one 3000, two 1000s, and therefore, three 2000s (to make up the 6 spends). A key constraint is that each traveler had different spends in the two countries they visited.

From the Brelosian citizen's observation, Kira spent 2000 Brins and Lian spent 3000 Brins in Brelosia. Since Lian spent 3000, this accounts for the single 3000 spend. Therefore, Kira's spend in Aurevia cannot be 2000 (because Kira's spends must be unique) and cannot be 3000. Kira's spend in Aurevia must be 1000 Aurels.

Now, we set up equations for the exchange rates. Let the exchange rates to Zentars (Z) be:
1 Aurel = $a$ Zentars
1 Brin = $b$ Zentars
1 Crown = $c$ Zentars

We are given that 1 Crown = 0.5 Zentars, so $c=0.5$.

The Travel Cost is the sum of the Flight Cost (FC) and the local spends converted into the currency of the citizen making the observation. Jano's FC is 4000 Z. Kira and Lian have FCs of 5000 Z and 6000 Z, in some order.

Let us evaluate Kira's Travel Cost:
Kira's FC is ${\mathrm{FC}}_K$ in Zentars. Kira spent 1000 A and 2000 B.
In Brelosia, Kira's Travel Cost is 4000 B:

$\frac{{\mathrm{FC}}_K+1000a}{b}+2000=4000$

This simplifies to: ${\mathrm{FC}}_K+1000a=2000b$.

In Aurevia, Kira's Travel Cost is 8000 A:

$\frac{{\mathrm{FC}}_K+2000b}{a}+1000=8000$

This simplifies to: ${\mathrm{FC}}_K+2000b=7000a$.

By substituting $2000b$ from the first equation into the second:

${\mathrm{FC}}_K+({\mathrm{FC}}_K+1000a)=7000a$

$2{\mathrm{FC}}_K=6000a$ or ${\mathrm{FC}}_K=3000a$.

We know Kira's Flight Cost is either 5000 or 6000.
If ${\mathrm{FC}}_K=5000$, then $a=\frac{5}{3}$ and $b=\frac{10}{3}$.
If ${\mathrm{FC}}_K=6000$, then $a=2$ and $b=4$.

We check Lian's Travel Cost to determine the correct case. Lian spent 3000 B and some amount $S_{\mathrm{LC}}$ in Cyrenia. In Cyrenia (where 1 C = 0.5 Z), her Travel Cost was 36000 C:

$\frac{{\mathrm{FC}}_L+3000b}{0.5}+S_{\mathrm{LC}}=36000$

$2{\mathrm{FC}}_L+6000b+S_{\mathrm{LC}}=36000$

If ${\mathrm{FC}}_K=5000$, then ${\mathrm{FC}}_L=6000$ and $b=\frac{10}{3}$. The equation becomes: $12000+20000+S_{\mathrm{LC}}=36000$, meaning $S_{\mathrm{LC}}=4000$. This is invalid because the only allowed spends are 1000, 2000, or 3000.
If ${\mathrm{FC}}_K=6000$, then ${\mathrm{FC}}_L=5000$ and $b=4$. The equation becomes: $10000+24000+S_{\mathrm{LC}}=36000$, meaning $S_{\mathrm{LC}}=2000$. This is valid!

So, $a=2$ (1 Aurel = 2 Zentars) and $b=4$ (1 Brin = 4 Zentars).
Now we determine Jano's spends. The total spends used so far are 1000 (Kira in A), 2000 (Kira in B), 3000 (Lian in B), and 2000 (Lian in C). We have accounted for one 1000, two 2000s, and one 3000. Since exactly two 1000s and three 2000s must be used in total, Jano's spends in Aurevia ($S_{\mathrm{JA}}$) and Cyrenia ($S_{\mathrm{JC}}$) must be one 1000 and one 2000.

Jano's Travel Cost in Aurevia is 3500 A. His Flight Cost is 4000 Z.

$\frac{4000+0.5S_{\mathrm{JC}}}{a}+S_{\mathrm{JA}}=3500$

Substituting $a=2$:

$2000+0.25S_{\mathrm{JC}}+S_{\mathrm{JA}}=3500$

$S_{\mathrm{JA}}+0.25S_{\mathrm{JC}}=1500$

Testing the remaining values {1000, 2000} for Jano's spends:
If $S_{\mathrm{JC}}=2000$, then $S_{\mathrm{JA}}+500=1500$, yielding $S_{\mathrm{JA}}=1000$. This works perfectly!

Finally, we calculate Jano's total spend in Aurels. Jano spent 1000 Aurels in Aurevia. In Cyrenia, he spent 2000 Crowns.
We convert the 2000 Crowns to Aurels:
1 Crown = 0.5 Zentars
1 Aurel = 2 Zentars
Therefore, 1 Crown = 0.25 Aurels.
2000 Crowns = $2000\times 0.25=500$ Aurels.

Adding them together, Jano's total spend in Aurels is:
1000 (spend in Aurevia) + 500 (spend in Cyrenia converted to Aurels) = 1500.