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How many numbers can be formed with the digits 2,4,4,3,7 which are greater than 40000?

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To solve the problem of how many numbers can be formed with the digits 2, 4, 4, 3, and 7 that are greater than 40000, we can follow these steps: ### Step 1: Identify the possible leading digits Since we need to form numbers greater than 40000, the leading digit (the first digit) must be either 4 or 7. ### Step 2: Case 1 - Leading digit is 4 If the leading digit is 4, the remaining digits to arrange are 2, 4, 3, and 7. #### Step 2.1: Count arrangements of remaining digits We have 4 digits (2, 4, 3, 7) to arrange. The number of arrangements of these 4 digits is calculated using the factorial of the number of digits: \[ \text{Arrangements} = 4! = 24 \] ### Step 3: Case 2 - Leading digit is 7 If the leading digit is 7, the remaining digits to arrange are 2, 4, 4, and 3. #### Step 3.1: Count arrangements of remaining digits Here, we have 4 digits (2, 4, 4, 3) to arrange. Since the digit 4 is repeated, we need to divide by the factorial of the count of the repeated digit: \[ \text{Arrangements} = \frac{4!}{2!} = \frac{24}{2} = 12 \] ### Step 4: Total arrangements Now, we sum the arrangements from both cases: \[ \text{Total arrangements} = \text{Arrangements with leading 4} + \text{Arrangements with leading 7} \] \[ \text{Total arrangements} = 24 + 12 = 36 \] ### Final Answer Thus, the total number of numbers that can be formed with the digits 2, 4, 4, 3, and 7 that are greater than 40000 is **36**. ---
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