A Hotel Company located in the south of the country, signed at Banco La Costeña, on March 24, 2023, two promissory notes and a bill of exchange for the following amounts: Q.300,000.00; Q.250,000.00 and Q.150,000.00, the expiration dates being October 28, 2023, December 15, 2023 and March 30, 2024 in the order of the documents. For the first promissory note it recognizes the interest rate of 4% every four months of exact simple interest and for the second promissory note the rate of 3% ordinary simple interest. The company will pay the three documents in a single payment on August 30, 2023, recognizing the rate of 3 3/4% ordinary simple quarterly interest. How much is the value of the single payment that the Hotel Company must make?

To find the value of the single payment that the Hotel Company must make, we need to calculate the current values of the promissory notes and the bill of exchange and then sum them up.

Let's start with the first promissory note, which has an amount of Q.300,000.00 and an expiration date of October 28, 2023. The interest rate is 4% every four months of exact simple interest. To find the current value, we need to calculate the interest for the period from March 24, 2023, to August 30, 2023.

The time period is 5 months, and the interest rate is 4% every four months. So, we can calculate the interest using the formula:

$$\text{Interest} = \frac{\text{Principal} \times \text{Rate} \times \text{Time}}{100}$$

Therefore, the interest for the first promissory note is:

$$\text{Interest} = \frac{300,000 \times 4 \times 5}{100} = 60,000$$

The current value of the first promissory note is:

$$\text{Current Value} = \text{Principal} + \text{Interest} = 300,000 + 60,000 = 360,000$$

Now, let's move on to the second promissory note, which has an amount of Q.250,000.00 and an expiration date of December 15, 2023. The interest rate is 3% ordinary simple interest. To find the current value, we need to calculate the interest for the period from March 24, 2023, to August 30, 2023.

The time period is 5 months, and the interest rate is 3%. Using the same formula as before, the interest for the second promissory note is:

$$\text{Interest} = \frac{250,000 \times 3 \times 5}{100} = 37,500$$

The current value of the second promissory note is:

$$\text{Current Value} = \text{Principal} + \text{Interest} = 250,000 + 37,500 = 287,500$$

Finally, let's calculate the current value of the bill of exchange, which has an amount of Q.150,000.00 and an expiration date of March 30, 2024. The interest rate is 3% ordinary simple quarterly interest. To find the current value, we need to calculate the interest for the period from March 24, 2023, to August 30, 2023.

The time period is 5 months, but the interest rate is quarterly. We need to convert the time period to quarters, which is $\frac{5}{3}$. Using the same formula, the interest for the bill of exchange is:

$$\text{Interest} = \frac{150,000 \times 3 \times \frac{5}{3}}{100} = 7,500$$

The current value of the bill of exchange is:

$$\text{Current Value} = \text{Principal} + \text{Interest} = 150,000 + 7,500 = 157,500$$

Now, we can calculate the total value of the single payment that the Hotel Company must make by summing up the current values of the promissory notes and the bill of exchange:

$$\text{Total Value} = \text{Current Value of Promissory Note 1} + \text{Current Value of Promissory Note 2} + \text{Current Value of Bill of Exchange}$$
$$\text{Total Value} = 360,000 + 287,500 + 157,500 = 805,000$$

Therefore, the value of the single payment that the Hotel Company must make is Q.805,000.00.
\textbf{Answer: $$\boxed{\text{Q.805,000.00}}$}