No products in the cart.

Which term of the AP 21,18,15,......is …

CBSE, JEE, NEET, CUET

Question Bank, Mock Tests, Exam Papers

NCERT Solutions, Sample Papers, Notes, Videos

Install Now

Which term of the AP 21,18,15,......is 81?

Posted by Sachin Gothi Patidar 1 year, 5 months ago

MP Board > Class 10 > Mathematics

1 answers

Preeti Dabral 1 year, 5 months ago

Here the given AP is : 21,18,15,--------
Here a=21 and d=18-21=-3,a_n=-81
{tex}\mathrm{We}\;\mathrm{know}\;\mathrm{that}\;{\mathrm a}_{\mathrm n}=\mathrm a+(\mathrm n-1)\mathrm d{/tex}
{tex}\Rightarrow{/tex} -81=21+(n-1)(-3)
{tex}\Rightarrow{/tex} -81=21-3n+3

3n = 81+21+3=105
So n = {tex}\frac{105}{3}{/tex} = 35
So, -81 is the 35^th term of this AP

0Thank You

ANSWER

Related Questions

Solve the following pair of linear equation by the substitutional method (1) x+y=14 (2) s -t=3

Posted by Ansh Gupta 1 month, 3 weeks ago

MP Board > Class 10 > Mathematics

0 answers

For the following APs ? If they from

Posted by Piyush Singh 8 months, 4 weeks ago

MP Board > Class 10 > Mathematics

1 answers

8.4

Posted by Cherry Cherry 7 months, 3 weeks ago

MP Board > Class 10 > Mathematics

0 answers

This content has been hidden. One or more users have flagged this content as inappropriate. Once content is flagged, it is hidden from users and is reviewed by myCBSEguide team against our Community Guidelines. If content is found in violation, the user posting this content will be banned for 30 days from using Homework help section. Suspended users will receive error while adding question or answer. Question comments have also been disabled. Read community guidelines at https://mycbseguide.com/community-guidelines.html

Few rules to keep homework help section safe, clean and informative.

Don't post personal information, mobile numbers and other details.
Don't use this platform for chatting, social networking and making friends. This platform is meant only for asking subject specific and study related questions.
Be nice and polite and avoid rude and abusive language. Avoid inappropriate language and attention, vulgar terms and anything sexually suggestive. Avoid harassment and bullying.
Ask specific question which are clear and concise.

Remember the goal of this website is to share knowledge and learn from each other. Ask questions and help others by answering questions.

Posted by Amit Meena 5 months, 4 weeks ago

MP Board > Class 10 > Mathematics