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Solve the following system of… (Class 10 Maths 2024, Q21)

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MathsCBSE Class 10 · Standard · Board exam 2024, set 30/1/1 · 2 marks · Very short answer

CBSE Class 10 Mathematics Standard 2024: question 21

Set in the CBSE Class 10 board exam of 2024, paper 30/1/1, section B, question 21, for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q21 · 2 marks · Very short answerPair of Linear Equations in Two Variables

Solve the following system of linear equations and and verify your answer.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 30/1/1.

Hints

Open one hint at a time and try again before the next.

Hint 1

Try making the coefficients of equal in size but opposite in sign.

Hint 2

Multiply the first equation by 7 and the second by 2, then add.

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

  1. …(i), …(ii). Multiply (i) by 7 and (ii) by 2: and . Adding gives .

    1 mark

  2. So . Substituting in (i): . Hence .

    ½ mark

  3. Verification: in (i), ✓; in (ii), ✓. Both equations are satisfied.

    ½ mark

Answer: x = 1, y = 1

Where the marks are

  • Eliminates a variable correctly to reach (1 mark)
  • Obtains (½ mark)
  • Verifies the solution in both equations (½ mark)

Revise the chapter

Practise this chapterBoard-style questions from Pair of Linear Equations in Two Variables, one at a time, marked against the answer key and marking points.Back to the full paper2024 board paper, set 30/1/1 (Standard): every question, by section.

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.