Question

Find the sum of first 15 terms of the ap 13,17,21,25...​

Answer 1

Answer:

615

Step-by-step explanation:

a = 13 d = 4 n = 15

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

= 15/2 (2(13) + (15-1)4)

= 15/2 (26 + 56)

= 15/2 × 82

= 15 × 41

= 615

sum of 15 terms of AP is 615

hope you get your answer

Answer 2

Answer:

615

Step-by-step explanation:

a = 13 d = 4 n = 15

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

= 15/2 (2(13) + (15-1)4)

= 15/2 (26 + 56)

= 15/2 × 82

= 15 × 41

= 615

sum of 15 terms of AP is 615

hope you get your answer