Find the sum of all two digit numbers wh | Class 11 Mathematics Chapter Sequence and Series, Sequence and Series NCERT Solutions

Question:

Find the sum of all two digit numbers which when divided by 4, yields 1 as remainder.

Answer:

The two-digit numbers, which when divided by 4, yield 1 as remainder, are

13, 17, … 97.

This series forms an A.P. with first term 13 and common difference 4.

Let n be the number of terms of the A.P.

It is known that the nth term of an A.P. is given by, an = a + (n –1) d

∴97 = 13 + (n –1) (4)

⇒ 4 (n –1) = 84

⇒ n – 1 = 21

⇒ n = 22

Sum of n terms of an A.P. is given by,

$S subscript n space equals space n over 2 space open square brackets 2 a space plus space open parentheses n minus 1 close parentheses d close square brackets therefore space S subscript 22 space equals space 22 over 2 space open square brackets 22 open parentheses 13 close parentheses space plus space open parentheses 22 minus 1 close parentheses open parentheses 4 close parentheses close square brackets space space space space space space space space space space space space space equals space 11 open square brackets 26 space plus space 84 close square brackets space space space space space space space space space space space space space equals space 1210$

Thus, the required sum is 1210.

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Study Tips for Answering NCERT Questions:

NCERT questions are designed to test your understanding of the concepts and theories discussed in the chapter. Here are some tips to help you answer NCERT questions effectively:

Read the question carefully and focus on the core concept being asked.
Reference examples and data from the chapter when answering questions about Sequence and Series.
Review previous year question papers to get an idea of how such questions may be framed in exams.
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Discuss your answers with your teachers or peers to get feedback and improve your understanding.

Comments

Siddhant Saxena
2019-09-19 19:39:28

Thanks

Shivangi Mishra
2019-09-14 11:43:16

kindly try to change the background theme.

Yashraj
2019-09-06 22:21:24

Excellent

Sr
2019-07-20 16:40:28

Excellent

Preetam
2016-10-14 01:28:02

Thanks

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Welcome to the NCERT Solutions for Class 11 Mathematics - Chapter . This page offers a step-by-step solution to the specific question from Excercise 5 , Question 6: Find the sum of all two digit numbers which when divided by 4, yields 1 as remainder.....

Find the sum of all two digit numbers wh | Class 11 Mathematics Chapter Sequence and Series, Sequence and Series NCERT Solutions

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