Question

In arithmetic sequence 7, 11, 15,.. . What is the difference between 1st and 21st term? What is the difference between 20th term and 40th term? What is the difference between the sum of first 20 terms and sum of the next 20 terms

Answer 1

Answer:

a =7

d=4

as we know that twenty first term will be

a+20d

7+20*4=87

so difference between 21st and 1st trm will be 80