Question

the first term and common difference of an arithmetic progression are 2 and 1 respectively.The arithmetic mean of the first 21 terms of the progression is?​

Answer 1

Answer:nth term of AP =a+(n-1)d

6th term of AP=20=a+5d ………….(1)

11 the term of AP=30=a+10d……….(2)

Solving (1) and (2) we get

a=10 and d=2

Step-by-step explanation: