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Bihar Board Class 9 Mathematics · Ch 3: The World of Numbers

Bihar Board Class 9 Mathematics · Ch 3: The World of Numbers is an online chapter test in the Bihar Board Class 9 pattern, covering The World of Numbers. Attempt it on SeatBeat with a timer like the real exam, then see a detailed solution for every question and your score and weak-topic analysis.

30
Questions
20
Minutes
30
Marks
None
Negative marking
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Topics in this test

TopicQuestions
The World of Numbers30

Difficulty: 7 medium · 23 hard

The World of Numbers MCQ questions with answers

The first 3 of 30 questions. Unlock the series for the rest, each with a solution.

  1. Q1. If $x=3+2\sqrt{2}$, then the value of $x+\frac{1}{x}$ is:

    यदि $x=3+2\sqrt{2}$ हो, तो $x+\frac{1}{x}$ का मान है:

    • A. $3$
    • B. $6$
    • C. $4\sqrt{2}$
    • D. $6+4\sqrt{2}$
    Solution

    $\frac{1}{x}=\frac{1}{3+2\sqrt{2}}=3-2\sqrt{2}$ after rationalising, so $x+\frac{1}{x}=(3+2\sqrt{2})+(3-2\sqrt{2})=6$.

    परिमेयकरण के बाद $\frac{1}{x}=\frac{1}{3+2\sqrt{2}}=3-2\sqrt{2}$, अतः $x+\frac{1}{x}=(3+2\sqrt{2})+(3-2\sqrt{2})=6$।

  2. Q2. Assertion (A): $\frac{22}{7}$ is a rational number. Reason (R): Every number whose decimal expansion is non-terminating is irrational. Choose the correct option.

    अभिकथन (A): $\frac{22}{7}$ एक परिमेय संख्या है। कारण (R): प्रत्येक वह संख्या जिसका दशमलव प्रसार असांत है, अपरिमेय होती है। सही विकल्प चुनिए।

    • A. Both A and R are true and R is the correct explanation of A / A और R दोनों सत्य हैं तथा R, A की सही व्याख्या है
    • B. A is false but R is true / A असत्य है परंतु R सत्य है
    • C. A is true but R is false / A सत्य है परंतु R असत्य है
    • D. Both A and R are false / A और R दोनों असत्य हैं
    Solution

    $\frac{22}{7}$ is rational (ratio of integers), so A is true, but R is false because non-terminating recurring decimals are rational.

    $\frac{22}{7}$ परिमेय है (पूर्णांकों का अनुपात), अतः A सत्य है, परंतु R असत्य है क्योंकि असांत आवर्ती दशमलव परिमेय होते हैं।

  3. Q3. Three of the following numbers are of the same kind and one is different. The 'odd one out' is:

    निम्नलिखित में से तीन संख्याएँ एक ही प्रकार की हैं और एक भिन्न है। 'विषम (odd one out)' है:

    • A. $0.1011011101111\ldots$
    • B. $\sqrt{2}$
    • C. $\sqrt{16}$
    • D. $\pi$
    Solution

    $\sqrt{2},\ \pi,\ 0.1011011101111\ldots$ are irrational (non-terminating non-recurring), but $\sqrt{16}=4$ is rational.

    $\sqrt{2},\ \pi,\ 0.1011011101111\ldots$ अपरिमेय हैं (असांत अनावर्ती), परंतु $\sqrt{16}=4$ परिमेय है।

Frequently asked questions

How many questions are in the Bihar Board Class 9 Mathematics · Ch 3: The World of Numbers?

30 questions for 30 marks, to be answered in 20 minutes.

Is there negative marking in the Bihar Board Class 9 Mathematics · Ch 3: The World of Numbers?

No — wrong answers are not penalised in this test.

Which topics does the Bihar Board Class 9 Mathematics · Ch 3: The World of Numbers cover?

The World of Numbers (30 questions).

Is the Bihar Board Class 9 Mathematics · Ch 3: The World of Numbers free?

It is part of the BSEB Class 9 Test Series 2027 — Chapter-wise + Full Tests (36 tests, ₹99). You can first try English · Ch 1: Dharam Juddha for free.

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