There are 91 oranges in a basket. If 2/7 of the oranges are bad, how many are good? If P - 3/8 = 5/8, find P. Express 15 cm as a decimal of 1 km. If 9.8 X 1.89 = 18.522, find 98 X 189.

Total oranges = 91.
Fraction of bad oranges = $\frac{2}{7}$.
Number of bad oranges $= \frac{2}{7} \times 91$.

There are 26 bad oranges.

Number of good oranges = Total oranges - Number of bad oranges.

There are 65 good oranges.

The calculated number of good oranges is 65, which corresponds to option C.

The final answer is $\boxed{\text{C. 65}}$.

The given equation is $P - \frac{3}{8} = \frac{5}{8}$.
To find $P$, add $\frac{3}{8}$ to both sides of the equation.

Since the fractions have the same denominator, add the numerators.

The calculated value of $P$ is 1, which corresponds to option C.

The final answer is $\boxed{\text{C. 1}}$.

We know that $1 \text{ km} = 1000 \text{ m}$.
We also know that $1 \text{ m} = 100 \text{ cm}$.
Therefore, $1 \text{ km} = 1000 \text{ m} \times 100 \text{ cm/m} = 100,000 \text{ cm}$.

This means we need to find the value of $\frac{15 \text{ cm}}{1 \text{ km}}$ in decimal form.

The calculated value is 0.00015, which corresponds to option D.

The final answer is $\boxed{\text{D. 0.00015}}$.

We are given $9.8 \times 1.89 = 18.522$.
We need to find $98 \times 189$.

Rearrange the terms:

We know $9.8 \times 1.89 = 18.522$.
We also know $10 \times 100 = 1000$.

Multiplying by 1000 shifts the decimal point three places to the right.

The final answer is $\boxed{\text{18522}}$.