CBSE Class 10 Answered

If a student has joined a group that has mean weight 25 kg  and the group mean weight with added student weight is still 25 kg , then weight of the student who has joined the group is also 25 kg.

---------------------------------------

If n^th term of A.P. is ( p n + q ) , then

p n + q = a + ( n-1 ) d  ........................... (1)

where a is the first term and d is common difference .

Equation (1) can be written as

p n + q = (a -d)+ ( n d ) 

Hence we get   ( n d ) = q

Hence common difference d = q/n