From a class of 40 students, in how many ways can five students be chosen
(ii) As subject monitor (one from each subject)

Answer

To solve the problem of choosing 5 students from a class of 40 to be subject monitors (one from each subject), we can break it down into the following steps:

### Step 1: Understand the Problem
We need to choose 5 students from a total of 40 students. Each of these 5 students will represent a different subject.

### Step 2: Choose 5 Students
To choose 5 students from 40, we use the combination formula:
\[ \binom{n}{r} = \frac{n!}{r!(n-r)!} \]
where \( n \) is the total number of students (40) and \( r \) is the number of students to choose (5).

So, we calculate:
\[ \binom{40}{5} = \frac{40!}{5!(40-5)!} = \frac{40!}{5! \cdot 35!} \]

### Step 3: Calculate \(\binom{40}{5}\)
Now, we can simplify the calculation:
\[ \binom{40}{5} = \frac{40 \times 39 \times 38 \times 37 \times 36}{5 \times 4 \times 3 \times 2 \times 1} \]

Calculating the numerator:
\[ 40 \times 39 = 1560 \]
\[ 1560 \times 38 = 59280 \]
\[ 59280 \times 37 = 2193360 \]
\[ 2193360 \times 36 = 78960960 \]

Calculating the denominator:
\[ 5 \times 4 \times 3 \times 2 \times 1 = 120 \]

Now, divide the numerator by the denominator:
\[ \binom{40}{5} = \frac{78960960}{120} = 657174 \]

### Step 4: Arrange the Chosen Students
Since we need to assign each of the 5 chosen students to a different subject, we need to arrange these 5 students. The number of ways to arrange 5 students is given by \( 5! \):
\[ 5! = 5 \times 4 \times 3 \times 2 \times 1 = 120 \]

### Step 5: Total Ways to Choose and Arrange
Now, we multiply the number of ways to choose the students by the number of ways to arrange them:
\[ \text{Total Ways} = \binom{40}{5} \times 5! = 657174 \times 120 \]

Calculating the total:
\[ 657174 \times 120 = 78860880 \]

### Final Answer
Thus, the total number of ways to choose and arrange 5 students as subject monitors is:
\[ \boxed{78860880} \]