Out of the 75 birders, 15 wanted to see only sunbird, 10 wanted to see only flycatcher, 12 wanted to see both sunbird and nuthatch, 15 wanted to see only bee-eater, 13 wanted to see both sunbird and bee-eater, 5 wanted to see both flycatcher and nuthatch and the remaining wanted to see only nuthatch.
How many birders wanted to see only one bird?
A. 30
B. 40
C. 45
D. 50

Options

A. A
B. D
C. B
D. C

Answer

To solve the problem step-by-step, we can use a Venn diagram to visualize the distribution of birders who want to see different types of birds. Here's how to approach the question:

### Step 1: Identify the Groups
We have the following groups based on the information given:
- **Only Sunbird (S)**: 15 birders
- **Only Flycatcher (F)**: 10 birders
- **Only Bee-eater (B)**: 15 birders
- **Both Sunbird and Nuthatch (S ∩ N)**: 12 birders
- **Both Sunbird and Bee-eater (S ∩ B)**: 13 birders
- **Both Flycatcher and Nuthatch (F ∩ N)**: 5 birders

### Step 2: Calculate the Remaining Birders
We know there are a total of 75 birders. To find out how many wanted to see only Nuthatch (N), we first need to sum up the known groups:

- Total from the groups:
- Only Sunbird: 15
- Only Flycatcher: 10
- Only Bee-eater: 15
- Both Sunbird and Nuthatch: 12
- Both Sunbird and Bee-eater: 13
- Both Flycatcher and Nuthatch: 5

Calculating the total:
\[ 15 + 10 + 15 + 12 + 13 + 5 = 70 \]

### Step 3: Determine the Number of Birders Who Want Only Nuthatch
Now, we subtract the total from the overall number of birders:
\[ 75 - 70 = 5 \]
Thus, 5 birders want to see only Nuthatch.

### Step 4: Calculate the Total Number of Birders Wanting Only One Bird
Now, we can find the total number of birders who wanted to see only one type of bird:
- Only Sunbird: 15
- Only Flycatcher: 10
- Only Bee-eater: 15
- Only Nuthatch: 5

Adding these together:
\[ 15 + 10 + 15 + 5 = 45 \]

### Final Answer
Thus, the total number of birders who wanted to see only one bird is **45**.