Question

the first term of two AP are equal and their ratios of the common difference is 1 : 2 .If the 7th term of an ap and the 21st term of 2nd ap are 23 and 125 respectively find two A.P.S​

Answer 1

Answer:

First AP 5,8,11,14,17.....

Second AP 5,11,17,21.......

Step-by-step explanation:

Let the first term of both the APs be a and common difference of first AP be d and of second AP be 2d

For First AP 7th term is 23

so a+(7-1)d=23

or a+6d=23

Now For the Second AP 21st term is 125

so a+(21-1)2d=125

a+40d=125

Solving the two equations

34d=102

Or d=3

Now using a+6d=23

a+18=23

or a=5

So the First AP 5,8,11,14,17.....

the Second AP 5,11,17,21.......