Question

Q.15. In an AP the 10th term is 2
17. what is the sum of its first
19 terms ?​

Answer 1

Explanation:

◦•●◉✿In an A.P., uₙ = a + (n-1)d

u₁₀ = 13

a + 9d = 13

Sₙ = n/2 {2a + (n-1)d}

S₁₉ = 19/2 {2a + 18d}

= 19 {a + 9d}

= 19 {13}

= 247✿◉●•◦