Math, asked by aloksatishchandrasha, 3 months ago

what is the sum of the first 20 terms of an Ap if a = 4 and t20=36? Please answer I will mark you brainliest..plzzz​

Answers

Answered by anmol1383
11

Answer:

Given,

a= 4

20th term or last term for finding sum = 36

number of term = 20

Sum of n term =

(a + l) \times n \div 2(a+l)×n÷2

where

a= first term = 4

l = last term = 36

and n = no. of terms = 20

After substituting value

Sum = (4 + 36)X 20/2

= 40 X 10

= 400


aloksatishchandrasha: actually I want this in a simple way
zainab444: ohhh
zainab444: ok
zainab444: I know this way only
zainab444: ok
zainab444: but plz mark me as a brainlist plzz
shailasherigar68: which formula is used here
aloksatishchandrasha: it is there in arithmetic progression
Answered by zainab444
6

Step-by-step explanation:

Given,

a= 4

20th term or last term for finding sum = 36

number of term = 20

Sum of n term =

(a + l) \times n \div 2(a+l)×n÷2

where

a= first term = 4

l = last term = 36

and n = no. of terms = 20

After substituting value

Sum = (4 + 36)X 20/2

= 40 X 10

= 400

Similar questions