Question

In



a.P 4th term and 8th are in ratio 1:2 if 10th term is 30 find



a.P

Answer 1

Answer:

3 , 6 , 9 , 12 , 15....................... is the A.P.

Step-by-step explanation:

We know that,

a4 : a8 = 1:2

Solving them,

a + 3d : a + 7d = 1:2

Cross-multiplying them,

(a + 3d)2 = a + 7d

2a + 6d = a + 7d

2a - a = 7d - 6d

a = d                                                      ------------------(1)

Given that,

a10 = 30

a + 9d = 30

From equation (1) we get,

a + 9a = 30

10a = 30

a = 3                                                      ------------------(2)

By equation (1) and (2) we get,

a = d = 3

Then the a.p. is :----

a , a + d , a + 2d , a + 3d , a + 4d.......................

Putting the values :----

3 , 3 + 3 , 3 + 2(3) , 3 + 3(3) , 3 + 4(3).......................

Solving them :----

3 , 6 , 3 + 6 , 3 + 9 , 3 + 12.......................

Solving it more :----

3 , 6 , 9 , 12 , 15.......................

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Answer 2

Step-by-step explanation:

this is the answer asked for above question asked