Question

find sum of:3,8,13,18,,,,,,,,,,,,,upto 20th term​

Answer 1

Answer:

1.Our formula is: an = a1 + (n-1)d.

2.Here, 'd' is the common difference, 2, and 'n' is the 20 since we're looking for the 20th term.

3.'a1' is the first term, and 'an' should be 'a20' , which is the 20th term.

Answer 2

Step-by-step explanation:

An=a+(n-1)d

=3+(20-1)5

=3+19×5

=3+95

An=98

that means,A20th =98.

Sn = n/2 +(n-1)d

= 20/2+(20-1)5

=10+95

S20= 105.

I hope you are understand .

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