The 80th term of an arithmetic sequence is twice the 30th term. If the first term of the sequence is 7, what is the 40th term?

Respuesta :

It seems that "d" or the common difference is a number that makes the sequence go into the larger positive realm of numbers. Therefore, 2*(7+30d)=7+80d. d=35/100. Now just do 7 + 40(35/100) = 21. 21 is your answer!