The sum of all the positive factors of 45 is

Options

A. 78
B. 26
C. 87
D. 94

Answer

To find the sum of all the positive factors of 45, we will follow these steps:

### Step 1: Identify the positive factors of 45
To find the positive factors, we need to determine which numbers divide 45 without leaving a remainder. The positive factors of 45 are:
1. 1 (since 1 × 45 = 45)
2. 3 (since 3 × 15 = 45)
3. 5 (since 5 × 9 = 45)
4. 9 (since 9 × 5 = 45)
5. 15 (since 15 × 3 = 45)
6. 45 (since 45 × 1 = 45)

Thus, the positive factors of 45 are: **1, 3, 5, 9, 15, 45**.

### Step 2: Sum the positive factors
Now, we will add all the positive factors we found:

\[ 1 + 3 + 5 + 9 + 15 + 45 \]

Calculating this step-by-step:
- First, add 1 and 3:
\[ 1 + 3 = 4 \]
- Next, add 5:
\[ 4 + 5 = 9 \]
- Now, add 9:
\[ 9 + 9 = 18 \]
- Then, add 15:
\[ 18 + 15 = 33 \]
- Finally, add 45:
\[ 33 + 45 = 78 \]

### Conclusion
The sum of all the positive factors of 45 is **78**.

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