write an A. P. in which a=10 and d is any natural number. find the sum of first 20 terms using formula.​

The Sum of first 20 terms of required AP is 2100.

Justification:

Let us suppose d is equal to 10,

then,

Structure of AP => a, a + d, a + 2d

AP => 10, 20, 30, 40...

Now,

Sn = n/2(2a + (n - 1)d)

Sn = 20/2(2 × 10 + (20 - 1)10)

Sn = 10(20 + 190)

Sn = 10 × 210

Sn = 2100.

Here, a = 10 . Let d= 5. The A.P. is 10,15,20..

Sn = n/2(2a + (n - 1)d)

Hence, the sum of first 20 terms is 1150.

connie < felicia < stew

step-by-step explanation:

stew:

we need to find the slope

m = (y2-y1)/ (x2-x1)

    = (2650-795)/(10-3)

    = 1855/7

265 words per minute

connie:

we need to find the slope

m = (y2-y1)/ (x2-x1)

we have two points (0,0) and (4,800)

m = (800-0)/(4-0)

  m = 800/4

    200 words per minute

felicia:

260 words per minute

200< 260 < 265

connie < felicia < stew

c: lkllmn.

hope it's you