Math Problem Statement

The units digit of a two-digit number exceeds the tens digit by 2. Find the number if it is 4 times the sum of its digits

Solution

Let the two-digit number be represented as 10t+u10t + u, where tt is the tens digit and uu is the units digit.

Step 1: Setting up the first condition

The problem states that "the units digit exceeds the tens digit by 2." Therefore, we have the equation:

u=t+2u = t + 2

Step 2: Setting up the second condition

The problem also states that "the number is 4 times the sum of its digits." The sum of the digits is t+ut + u, and the number itself is 10t+u10t + u. Therefore, the second equation is:

10t+u=4(t+u)10t + u = 4(t + u)

Step 3: Substituting the first equation into the second

Substitute u=t+2u = t + 2 into the second equation:

10t+(t+2)=4(t+(t+2))10t + (t + 2) = 4(t + (t + 2))

Simplify both sides:

11t+2=4(2t+2)11t + 2 = 4(2t + 2)

11t+2=8t+811t + 2 = 8t + 8

Step 4: Solving for tt

Now, solve for tt by isolating it on one side of the equation:

11t8t=8211t - 8t = 8 - 2

3t=63t = 6

t=2t = 2

Step 5: Finding uu

Now that we know t=2t = 2, use the first equation to find uu:

u=t+2=2+2=4u = t + 2 = 2 + 2 = 4

Step 6: Verifying the solution

The number is 10t+u=10(2)+4=2410t + u = 10(2) + 4 = 24.

The sum of the digits is 2+4=62 + 4 = 6, and four times the sum of the digits is 4×6=244 \times 6 = 24, which matches the number itself.

Thus, the number is 24\boxed{24}.


Would you like further details or have any questions?

Here are 5 related questions you might explore:

  1. What if the units digit exceeded the tens digit by 3 instead of 2?
  2. How can this approach be generalized to solve similar problems with different relationships between the digits?
  3. What if the number was 5 times the sum of its digits instead of 4 times?
  4. How can we solve this type of problem when given a three-digit number?
  5. How does this problem relate to linear equations and algebraic techniques?

Tip: When solving word problems, clearly translate the conditions into equations to avoid confusion and simplify the solution process.

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Math Problem Analysis

Mathematical Concepts

Algebra
Linear Equations
Word Problems

Formulas

u = t + 2
10t + u = 4(t + u)

Theorems

Linear Equation Solving Techniques

Suitable Grade Level

Grades 6-8