NCERT Exemplar Solutions
Class 10 - Mathematics - CHAPTER 3: Pair of Linear Equations in Two Variables - Exercise 3.3
Question 18

Question. 18

Two numbers are in the ratio \(5:6\). If 8 is subtracted from each, the ratio becomes \(4:5\). Find the numbers.

Answer:

\(40\) and \(48\).

Detailed Answer with Explanation:

Step 1: Suppose the two numbers are in the form of \(5k\) and \(6k\).

Step 2: According to the question, if we subtract 8 from each number, the new ratio becomes \(4:5\).

This means:

\(\dfrac{5k - 8}{6k - 8} = \dfrac{4}{5}\)

Step 3: Now we cross multiply:

\(5 \times (5k - 8) = 4 \times (6k - 8)\)

Step 4: Multiply both sides:

\(25k - 40 = 24k - 32\)

Step 5: Bring like terms together:

\(25k - 24k = -32 + 40\)

Step 6: Simplify:

\(k = 8\)

Step 7: Put the value of \(k\) back into the numbers:

First number = \(5k = 5 \times 8 = 40\)

Second number = \(6k = 6 \times 8 = 48\)

Final Answer: The two numbers are \(40\) and \(48\).

NCERT Exemplar Solutions Class 10 – Mathematics – CHAPTER 3: Pair of Linear Equations in Two Variables – Exercise 3.3 | Detailed Answers