Question

AL
Find the sum of an AP 3, 7, 11, ..., up to 13 terms.​

Answer 1

Step-by-step explanation:

a=3

d=4

S¹³= 13/2[2a+d(n-1)]

=13/2(6+48)

=13/2x54

=13x27

now multiply yourself

answer will come ez

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Answer 2

The given series is 3,7,11,....

Here a=3,d=7−3=4

S n = 2n [2a+(n−1)d]

S 10 = 10 /2(2(3)+9(4)) .sum of first 10 terms

S 10 =5(6+36)=210

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