In a certain ocean region, the ratio of sharks to tuna to damselfish to gupples is 1 to 3 to 5 to 6. If there are 1,500 total fish in that region, how many of the fish are sharks?

Options

A. `15`
B. `100`
C. `150`
D. `450`

Answer

To solve the problem, we need to determine the number of sharks in a region where the ratio of sharks to tuna to damselfish to guppies is given as 1:3:5:6, and the total number of fish is 1,500.

### Step-by-Step Solution:

1. **Understand the Ratios**:
The ratio of sharks to tuna to damselfish to guppies is given as:
- Sharks = 1 part
- Tuna = 3 parts
- Damselfish = 5 parts
- Guppies = 6 parts

2. **Calculate the Total Parts**:
To find the total number of parts in the ratio, we add all the parts together:
\[ \text{Total parts} = 1 + 3 + 5 + 6 = 15 \]

3. **Set Up the Equation**:
Let \( x \) represent the number of sharks. Then, based on the ratio:
- Sharks = \( 1x \)
- Tuna = \( 3x \)
- Damselfish = \( 5x \)
- Guppies = \( 6x \)

The total number of fish can be expressed as:
\[ 1x + 3x + 5x + 6x = 15x \]

4. **Equate to Total Fish**:
We know the total number of fish is 1,500, so we set up the equation:
\[ 15x = 1500 \]

5. **Solve for \( x \)**:
To find \( x \), divide both sides of the equation by 15:
\[ x = \frac{1500}{15} = 100 \]

6. **Find the Number of Sharks**:
Since the number of sharks is \( 1x \), we substitute \( x \) back into the equation:
\[ \text{Number of sharks} = 1x = 1 \times 100 = 100 \]

### Final Answer:
The number of sharks in that region is **100**.