Question

in an AP 4th term is equal to 5times of first term , 8th term is one more than twice the 4th term . find the AP​

Answer 1

Answer:

3,7,11,15,....are in A. P

Step-by-step explanation:

t4 = 5a

a+3d = 5a

4a = 3d------(1)

t8 = 2(t4)+1

t8 = 2(5a)+1

a+7d = 10a+1

7d-1 = 9a

7d-1 = 9(3d/4)

28d-4 = 27d

d = 4. in (1)

4a = 3(4) = 12

a = 3

t1 = 3

t2 = 3+4 = 7

t3 = 3+2(4) = 11

t4 = 3+3(4) = 15

3,7,11,15,....are in A. P