Question 19 - CBSE Class 10 Sample Paper for 2026 Boards - Maths Standard [Term I] - Solutions of Sample Papers for Class 10 Boards

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Question 19 Assertion (A): The number 5n cannot end with the digit 0, where n is a natural number Reason (R): A number ends with 0, if its prime factorization contains both 2 and 5 Choose the correct option: (A) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A) (B) Both assertion (A) and reason (R) are true and reason (R) is not the correct explanation of assertion (A) (C) Assertion (A) is true but reason (R) is false. (D) Assertion (A) is false but reason (R) is true.Checking Assertion The number 5n cannot end with the digit 0, where n is a natural number Let’s put various values of n For n = 0, 5n = 50 = 1 For n = 0, 5n = 50 = 1 For n = 0, 5n = 50 = 1 For n = 0, 5n = 50 = 1 For n = 0, 5n = 50 = 1 So, 5n cannot end with digit 0 Thus, Assertion is true Checking Reason A number ends with 0, if its prime factorization contains both 2 and 5 This is true for all numbers ending with 0 Example: 10 = 2 × 5 20 = 2 × 2 × 5 90 = 3 × 3 × 2 × 5 Thus, Reason is true. Is Reason correct explanation for Assertion? 5n doesn’t end with zero because its prime factorisation does not have 2 and 5 Therefore, Reasoning is correct explanation for Assertion So, Assertion is true Reasoning is true and, Reasoning is correct explanation for Assertion So, the correct answer is (a)