Question

WhAt os the sum of 10term of an AP 41,36,31,26

Answer 1

Soln:-

The sum of 10term,

S10 = 185

Summation of n terms in A. P.

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

41,36,31,26. ..A.P.

a = 41, d = t2-t1 = 36-41 = -5

To find :-

S10 = 10/2 [2a+(10-1)d]

= 5[2(41) + 9(-5)]

= 5(82-45)

= 5(37)

= 185

Answer 2

Answer:

-590

Step-by-step explanation:

x = 41        d = -5

x₁₀  =  dn + (x-d)

     =   -5 * 41 + (41 - (-5))

     =   -159

sum = n/2 (x + xₙ)

       = 10/2 (41 + (-159))

        = - 590