The mean of 10 numbers 7 × 8 , 10 × 10 , 13 × 12 , 16 × 14 , … is

Step-by-step solution

Given that 7 , 10 , 13 - -   &   8 , 10 , 12 , - - -   ∈   A . P r t h   term of an A . P   ⇒   t r   =   a   + r - 1 d Here a   =   7 ,   d   =   3   &   a   =   8 ,   d   = 2 t r   = 3 r   + 4     &     t r   = 2 r   + 6 ∑ r = 1 10 ( 3 r + 4 ) ( 2 r + 6 ) = ∑ r = 1 10 6 r 2 + 26 r + 24 = 6 ∑ r = 1 10 r 2 + 26 ∑ r = 1 10 r +