Math, asked by alokjose00, 10 months ago

(1) Find the sum of the first 25 terms of each of the arithmetic sequences
below.
1) 11, 22, 33, ... ii) 12, 23, 34, ... iii) 21, 32, 43, ...
iv) 19, 28, 37, v) 1, 6, 11, ...​

Answers

Answered by soleclarkstella
30

Answer:

3,575, 3,600, 3,825, 3,775, 1525

Step-by-step explanation:

1. a=11, d=22-11=11

sum of n terms is n/2(2a+(n-1)d)

sum of 25 terms = 25/2 (2*11+(25-1)11)

                          = 25/2(22+264)

                          = 25/2 * 286

                          = 3,575

2. a=12, d= 23-12= 11

sum of 25 terms = 25/2 (2*12+(25-1)11)

                            = 25/2 (24+264)

                             = 25/2 *288

                            = 3,600

3. a= 21, d= 32-21= 11

sum of 25 terms= 25/2 (2*21+(25-1)11)

                           = 25/2 (42 + 264)

                           = 25/2 * 306

                           = 3,825

4. a= 19, d= 28-19= 11

sum of first 25 terms= 25/2(2*19+(25-1)11)

                                  = 25/2 (38+264)

                                  = 25/2 (302)

                                  = 3,775

5. a= 1 , d=6-1= 5

sum of first 25 terms= 25/2(2*1+(25-1)5)

                                 = 25/2 (2+120)

                                = 25/2 (122)

                                 = 1,525

hope it helped

Answered by jia39
15

Ur answer for this question are here !

Attachments:
Similar questions