Question

The sum of first 7 terms of an arithmetic sequence is 119 and the sum of first 11
terms is 275 .

a)what is its 4th term
b)what is its 6th term
c)what is its common difference

Answer 1

Please make the answer as the Brainliest one for this question.

Answer 2

Answer:

given: sum of 1st 7term of AP

the question Is in ap

a , a+d , a+2d....

Step-by-step explanation:

solution:

S7 = 119 that is given

we know the formula

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

Substitute the value.

119 =7/2(2a + 6d)

solve we get

a+3d =17

similarly

S11 = 275 that is given

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

substitution of the value

275 = 11/2(2a+10d)

solve we get

a +5d =25

we have 2 equation know

put 2 in 1 we get

2d=8

d =4

a +12 =17

a=5

so now the answer

a) is a4 = a+3d =17

b) is a6 =a+5d = 25

c) is d=4

HENCE this is the solution

#SPJ3.