Question

For an A.P , if t₈ = 36 , then S₁₅ = ​

Answer 1

Answer:

540

Step-by-step explanation:

t8 = 36 = a + 7d then

let us assume a = 1 then d = 5 ( because it makes 'd ' rational value)

let us check 1,1+5,6+5,11+5,16+5,21+5,26+5,31+5,36+5

it is correct

then t15 = 1 + (14*5)

t15 = 71

sum s15 = 15(1+71)/2

= 15 * 36

540

Answer 2

a+7d=36
Sum=n/2[2a+(n-1)d]
540
Explanation below