(a,b,c,d) the first three one is arithmetic sequence and the last three one is geometric sequence. d-a=3 b+c=?

Question

Please can anyone solve this realy hard sequence problem?

Answer 1

this problem is hard to solve because the wording that you have supplied is not clear.

 

the expressions "first three one" and "last three one" are unfortunately vague, but that's not the only confusing aspect of your writing.