Question

For the progression 9, 18, 27 ..... find
(1) the 20th term
(2) the sum of first 20 terms ​

Answer 1

Answer:

20th term = 9 + (20 - 1)×9

=9 + 9×20 + 9 = 9×20 = 180

here 1st term is 9 and common difference = 9

Sum of the 20 terms = (20 /2)(2×9 + 19×9)=

10×(9)×(21) =1890 Ans