Math, asked by sneha7819, 1 year ago

in an ap the first term is -5 and last term is 45.if the sum of all numbers in the ap is 120 then how many terms are there and what is the commom differnce

Answers

Answered by YasminGautam
3

Here's the solution.

If it is right then please Mark it as the brainiest.!!

Attachments:

YasminGautam: and the other formula that i've written is used when last term is given.
sneha7819: and another is t1 + tn
sneha7819: yes
YasminGautam: yup!
rohitbagoriya1977: ji
Arjun2727: The answer is not right
sneha7819: It's right
Arjun2727: The way you solve is not understable
sneha7819: hmm
sneha7819: cheak for another ans
Answered by Silicora
3

Answer:

Step-by-step explanation:

We have,

First term=a=(-5)

Last term= l=45

Then,

Sn= n/2( a+ l)

120= n/2(-5+45)

240= n(40)

n=6

No. Of terms=6

Common difference= d

120= 6/2(2×-5+5 d)

40=(-10) +5 d

d=50/5=10

Common difference=10


sneha7819: srry but it's not the right answer
sneha7819: yeah now it's correct thank u soo much
Silicora: Do you have another question.
sneha7819: yes wait
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