Question

find the sum of the first 10 terms of the AP 3 6 9 12 extra​

Answer 1

Step-by-step explanation:

here

a = 3

d = 6-3 = 3

n = 10

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

10/2 ( 2×3 + (10 - 1)3 )

5 ( 6 + 9 × 3 )

5 × 33

165

hence sum is 165

Answer 2

Answer:

Step-by-step explanation:

a=3

d=3 n=10

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

S10=10[2×3+(10-1)3]/2

     = 10 [6+27]/2

     =    5×33

      =165