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Question

Six times the present age of P exceeds the present age of Q by 46 years. After 10 years, six times Q's age will be 18 years less than five times P's age at that time. What is the present age of Q (in years)?

The correct answer is
2

Age Problem Calculation

This solution demonstrates how to determine the present age of Q using the information provided in the word problem involving P and Q. We will employ algebraic methods to solve the system of equations.

P and Q Present Ages Defined

To begin, let's assign variables to represent the unknown ages:

  • Let \(P\) denote the present age of person P in years.
  • Let \(Q\) denote the present age of person Q in years.

Formulating Age Equations from Statements

The problem provides two key pieces of information that can be converted into mathematical equations.

First Statement Equation

Statement: "Six times the present age of P exceeds the present age of Q by 46 years."

Translating this into an equation:

$6P = Q + 46 \quad (1)$

Second Statement Equation

Statement: "After 10 years, six times Q's age will be 18 years less than five times P's age at that time."

Ages after 10 years:

  • P's future age: \(P + 10\)
  • Q's future age: \(Q + 10\)

Translating the statement into an equation:

$6(Q + 10) = 5(P + 10) - 18$

Simplifying this equation:

$6Q + 60 = 5P + 50 - 18$

$6Q + 60 = 5P + 32$

Rearranging terms to isolate \(6Q\):

$6Q = 5P + 32 - 60$

$6Q = 5P - 28 \quad (2)$

Solving the Age Equations System

We now have a system of two linear equations:

  1. \(6P = Q + 46\)
  2. \(6Q = 5P - 28\)

We need to solve this system to find the value of \(Q\).

Step 1: Express Q in terms of P

From Equation (1), rearrange to solve for \(Q\):

\(Q = 6P - 46\)

Step 2: Substitute into Equation 2

Substitute the expression for \(Q\) into Equation (2):

$6(6P - 46) = 5P - 28$

Step 3: Solve for P's Age

Expand and solve the equation for \(P\):

$36P - 276 = 5P - 28$

Combine \(P\) terms:

$36P - 5P = 276 - 28$

$31P = 248$

Solve for \(P\):

$P = \frac{248}{31}$

$P = 8$

The present age of P is 8 years.

Step 4: Calculate Q's Age

Using the relationship from Step 1 (\(Q = 6P - 46\)) and the value \(P = 8\):

\(Q = 6(8) - 46\)

\(Q = 48 - 46\)

\(Q = 2\)

Final Answer: Q's Age

Therefore, the present age of Q is 2 years.

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Important Questions from Problem on Age

  1. The ratio of present ages of A and B is 7 : 8. After 6 years from now, the ratio of their ages will be 8 : 9. If C's present age is 10 years more than the present age of A, then the present age (in years) of C is:

  2. Three years ago, the ratio of the age of father to that of his son was 8 ∶ 3. After 4 years, their ages will be in the ratio 11 ∶ 5. What is the present age (in years) of the father?

  3. At present, A is younger than B by 8 years. If 4 years ago, their ages were in the ratio 1 ∶ 2, then what is the present age of B (in years)?

  4. Eight years ago, the ratio of ages of A and B was 5 ∶ 4. The ratio of their present ages is 6 ∶ 5. What will be the sum (in years) of the ages of A and B after 7 years from now?

  5. Ratio of the present age of a mother to that of the daughter is 7 ∶ 1. After 5 years the ratio will become 4 ∶ 1. What is the difference (in years) in their present ages?

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