(a) To buy a Treasury bill (T-bill) that matures to $10,000 in 12 months, you must pay $9700. What rate does this earn?

(b) If the bank charges a fee of $20 to buy a T-bill, what is the actual interest rate you earn?

a. P = Po + Po*r*t.

P = $10,000, Po = $9700, t = 1 yr. r = Annual % rate = ?.

b. P = Po + Po*r*t. Po = $9720, All other inputs remain the same. r = ?.

(a) To find the rate at which the T-bill earns, we can use the formula for simple interest:

Simple Interest = (Principal * Rate * Time)

Given that the T-bill matures to $10,000 in 12 months, and you have to pay $9700 to buy it, we can use the equation:

$10,000 - $9,700 = $9,700 * Rate * 1 year

$300 = $9,700 * Rate

Divide both sides by $9,700 to find the rate:

Rate = $300 / $9,700

Rate = 0.030927 or 3.09%

Therefore, the T-bill earns an annual rate of approximately 3.09%.

(b) To calculate the actual interest rate you earn after deducting the $20 fee, we can modify the equation. The fee is subtracted from the amount you receive at maturity:

$10,000 - $9,700 - $20 = $9,680 * Rate * 1 year

$280 = $9,680 * Rate

Divide both sides by $9,680 to find the rate:

Rate = $280 / $9,680

Rate = 0.02893 or 2.89%

Therefore, after considering the $20 fee, the actual interest rate you earn is approximately 2.89%.

To calculate the rate of return on a Treasury bill (T-bill), we need to use the formula for yield or rate of return. The formula is as follows:

Rate of Return = (Maturity Value - Purchase Price) / Purchase Price

Let's apply this formula to the given scenario:

(a) To buy a T-bill that matures to $10,000 in 12 months, at a purchase price of $9,700, we can calculate the rate of return as follows:

Rate of Return = (10,000 - 9,700) / 9,700

Rate of Return = 300 / 9,700

Rate of Return = 0.0309 or 3.09%

Therefore, the rate of return on the T-bill is 3.09%.

(b) If the bank charges a fee of $20 to buy the T-bill, we need to subtract this fee from the initial investment to get the actual purchase price. Let's recalculate the rate of return:

Actual Purchase Price = Purchase Price - Fee

Actual Purchase Price = 9,700 - 20

Actual Purchase Price = 9,680

Rate of Return = (10,000 - 9,680) / 9,680

Rate of Return = 320 / 9,680

Rate of Return = 0.0331 or 3.31%

Therefore, considering the fee, the actual rate of return on the T-bill is 3.31%.