Question

The first and last terms of A.P r 17 and 350.If the common difference is 9.How many terms r their and what is their sum???​

Answer 1

Answer:6973

Step-by-step explanation:

Tn=a+(n-1)d

350 = 17 + (n-1) 9

37 = n -1

n=38

Now,sum = n/2 (a+tn)

=38/2 (17+350)

=19×367

6973

Answer 2

Solution

a=17 , l=350 , d=9

We assume that there are n terms.

Tn=a+(n-1)d

350=17+(n-1)9

350=17+9n-9

350=8+9n

350-8=9n

342=9n

n=38

There are 38 terms.

sum=n/2[2a+(n-1)d]

=38/2[2(17)+(38-1)9]

=19[34+(37×9)]

=19(34+333)

=19(367)

=6973

Their sum is 6973.

Hope that it is helpfull.

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