Math Problem Statement

A, B, C, D, and E play a game of cards. A says to B, 'If you give me three cards, you will have as many as E has and if I give you three cards, you will have as many as D has.' A and B together have 10 cards more than what D and E together have. If B has two cards more than what C has and the total number of cards is 133, how many cards does B have?

Solution

Let's break down the problem step by step, using algebra to represent the unknowns.

Variables:

  • Let AA, BB, CC, DD, and EE represent the number of cards held by players A, B, C, D, and E respectively.

Given conditions:

  1. A's statement:

    • "If you (B) give me 3 cards, you will have as many as E has." B - 3 = E \quad \Rightarrow \quad B = E + 3 \tag{1}
    • "If I (A) give you 3 cards, you will have as many as D has." B + 3 = D \quad \Rightarrow \quad B = D - 3 \tag{2}
  2. Combined total of A and B vs D and E:

    • "A and B together have 10 cards more than D and E together." A + B = D + E + 10 \tag{3}
  3. Relation between B and C:

    • "B has 2 cards more than C." B = C + 2 \tag{4}
  4. Total number of cards:

    • "The total number of cards is 133." A + B + C + D + E = 133 \tag{5}

Solving the system of equations:

From equation (1)(1), we have B=E+3B = E + 3.
From equation (2)(2), we have B=D3B = D - 3.

Substitute these into equation (3)(3): A+B=D+E+10A + B = D + E + 10 Since B=E+3B = E + 3, we have: A+(E+3)=D+E+10A + (E + 3) = D + E + 10 Simplifying: A+E+3=D+E+10A + E + 3 = D + E + 10 A = D + 7 \tag{6}

Now we have:

  • A=D+7A = D + 7 (from equation (6)),
  • B=E+3B = E + 3 (from equation (1)),
  • B=D3B = D - 3 (from equation (2)),
  • B=C+2B = C + 2 (from equation (4)).

Let's substitute these into equation (5)(5) (the total number of cards): A+B+C+D+E=133A + B + C + D + E = 133 Using the relations for AA, BB, and CC: (D+7)+B+(B2)+D+(B3)=133(D + 7) + B + (B - 2) + D + (B - 3) = 133 Simplifying this: (D+7)+B+(B2)+D+(B3)=133(D + 7) + B + (B - 2) + D + (B - 3) = 133 2D+7+3B5=1332D + 7 + 3B - 5 = 133 2D+3B+2=1332D + 3B + 2 = 133 2D + 3B = 131 \tag{7}

Now, substitute B=D3B = D - 3 (from equation (2)) into equation (7)(7): 2D+3(D3)=1312D + 3(D - 3) = 131 2D+3D9=1312D + 3D - 9 = 131 5D9=1315D - 9 = 131 5D=1405D = 140 D=28D = 28

Now that we have D=28D = 28, substitute this back to find BB: B=D3=283=25B = D - 3 = 28 - 3 = 25

Thus, B has 25 cards.

Would you like further clarification on this solution? Here are some additional questions that can extend your understanding:

  1. How many cards does player A have?
  2. How many cards does player C have?
  3. How many cards does player E have?
  4. Can you verify the total number of cards by adding up all individual counts?
  5. How would the problem change if B had one card more than C instead of two?

Tip: When solving a system of equations, substituting early equations into later ones helps reduce the number of variables and simplifies the solution process.

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Math Problem Analysis

Mathematical Concepts

Algebra
System of Linear Equations

Formulas

B - 3 = E
B + 3 = D
A + B = D + E + 10
B = C + 2
A + B + C + D + E = 133

Theorems

Substitution in Systems of Equations

Suitable Grade Level

Grades 10-12