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A two digit number is four times the sum...

A two digit number is four times the sum and three times the product of its digits. Find the number:

A

A)12

B

B)22

C

C)14

D

D)24

Text Solution

AI Generated Solution

The correct Answer is:
To find the two-digit number that is four times the sum and three times the product of its digits, we can follow these steps: ### Step 1: Define the digits Let the two-digit number be represented as \( N \), where: - \( A \) is the tens digit, - \( B \) is the units digit. Thus, the number can be expressed as: \[ N = 10A + B \] ### Step 2: Set up the equations According to the problem: 1. The number \( N \) is four times the sum of its digits: \[ N = 4(A + B) \] 2. The number \( N \) is also three times the product of its digits: \[ N = 3(A \times B) \] ### Step 3: Substitute \( N \) From the first equation, we can substitute \( N \): \[ 10A + B = 4(A + B) \] Expanding this gives: \[ 10A + B = 4A + 4B \] ### Step 4: Rearrange the equation Rearranging the equation to isolate terms involving \( A \) and \( B \): \[ 10A - 4A = 4B - B \] This simplifies to: \[ 6A = 3B \] Dividing both sides by 3 gives: \[ 2A = B \] Thus, we can express \( B \) in terms of \( A \): \[ B = 2A \] ### Step 5: Substitute \( B \) into the second equation Now, substitute \( B = 2A \) into the second equation: \[ 10A + 2A = 3(A \times 2A) \] This simplifies to: \[ 12A = 6A^2 \] ### Step 6: Rearrange and factor Rearranging gives: \[ 6A^2 - 12A = 0 \] Factoring out \( 6A \): \[ 6A(A - 2) = 0 \] ### Step 7: Solve for \( A \) Setting each factor to zero gives: 1. \( 6A = 0 \) → \( A = 0 \) (not valid for a two-digit number) 2. \( A - 2 = 0 \) → \( A = 2 \) ### Step 8: Find \( B \) Using \( A = 2 \) to find \( B \): \[ B = 2A = 2 \times 2 = 4 \] ### Step 9: Form the two-digit number Now, substituting \( A \) and \( B \) back into the expression for \( N \): \[ N = 10A + B = 10(2) + 4 = 20 + 4 = 24 \] ### Conclusion The two-digit number is \( 24 \). ---
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