Which term of the progression –1, –3, –5, …. Is –39
  • a)
    21st
  • b)
    20th
  • c)
    19th
  • d)
    none of these
Correct answer is option 'B'. Can you explain this answer?

CA Foundation Question

Sagarika Shinde
Aug 17, 2018
The general formula for an arithmetic sequence is: 
a(n) = a + d(n-1) 

a : first term (-1) 
d : common difference (-2) 
n : number of the term you want. 

Plug in your values: 
a(n) = -1 - 2(n - 1) 

We can simplify that slightly if you like: 
a(n) = -1 - 2n + 2 
a(n) = 1 - 2n 

Now you can figure out the value of n when a(n) = -39: 
-39 = 1 - 2n 
-40 = -2n 
n = -40/-2 
n = 20 
It is the 20th term.

Niket Bhosale
Nov 14, 2018
1 to40 there are 20 odd &even numbers39 is the 20th odd number

Prashant Gupta
Aug 31, 2018
Solve it on calculatortype first term then add difference then press equal to button when it become -39 then you will see counter gt on left top corner of calculator is 21then take less one digit it becomes 20 hence proved,

This discussion on Which term of the progression 1, 3, 5, . Is 39a)21stb)20thc)19thd)none of theseCorrect answer is option 'B'. Can you explain this answer? is done on EduRev Study Group by CA Foundation Students. The Questions and Answers of Which term of the progression 1, 3, 5, . Is 39a)21stb)20thc)19thd)none of theseCorrect answer is option 'B'. Can you explain this answer? are solved by group of students and teacher of CA Foundation, which is also the largest student community of CA Foundation. If the answer is not available please wait for a while and a community member will probably answer this soon. You can study other questions, MCQs, videos and tests for CA Foundation on EduRev and even discuss your questions like Which term of the progression 1, 3, 5, . Is 39a)21stb)20thc)19thd)none of theseCorrect answer is option 'B'. Can you explain this answer? over here on EduRev! Apart from being the largest CA Foundation community, EduRev has the largest solved Question bank for CA Foundation.

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This discussion on Which term of the progression 1, 3, 5, . Is 39a)21stb)20thc)19thd)none of theseCorrect answer is option 'B'. Can you explain this answer? is done on EduRev Study Group by CA Foundation Students. The Questions and Answers of Which term of the progression 1, 3, 5, . Is 39a)21stb)20thc)19thd)none of theseCorrect answer is option 'B'. Can you explain this answer? are solved by group of students and teacher of CA Foundation, which is also the largest student community of CA Foundation. If the answer is not available please wait for a while and a community member will probably answer this soon. You can study other questions, MCQs, videos and tests for CA Foundation on EduRev and even discuss your questions like Which term of the progression 1, 3, 5, . Is 39a)21stb)20thc)19thd)none of theseCorrect answer is option 'B'. Can you explain this answer? over here on EduRev! Apart from being the largest CA Foundation community, EduRev has the largest solved Question bank for CA Foundation.