Math Problem Statement

The total age of the brother and sister is 46. Seven years ago, the sum of their ages was four times the brother’s age. What is the recent age of the brother and sister? Solution:

(B-7) (S-7) = 4(B-7)

S = 7 = 4

S = 11 years (present)

B=35 years (present)

Solution

The problem is almost solved correctly, but let’s clarify the approach to verify each step and correct any inaccuracies.

Problem Statement Recap:

  • Let BB and SS represent the current ages of the brother and sister, respectively.
  • Total age of the brother and sister is 46 years: B+S=46B + S = 46.
  • Seven years ago, the sum of their ages was four times the brother’s age.

Solution Steps:

  1. Express the situation from seven years ago:

    • Seven years ago, the brother’s age was B7B - 7, and the sister’s age was S7S - 7.
    • According to the problem, seven years ago, the sum of their ages was four times the brother’s age: (B7)+(S7)=4(B7)(B - 7) + (S - 7) = 4(B - 7)
  2. Simplify the equation from seven years ago: B+S14=4B28B + S - 14 = 4B - 28 Rearranging terms gives: S=3B14S = 3B - 14

  3. Use the current age relationship:

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Math Problem Analysis

Mathematical Concepts

Algebra
Linear Equations

Formulas

Age difference equations
Linear relationships

Theorems

Basic properties of linear equations

Suitable Grade Level

Grades 6-8