posted by Riana on .
the 10th term is 34 of arithmetic series and the sum of the 20th term is 710.what is the 25th term?
the difference between T10 and T20 is 10d. So, 10d=710-34=676
T25=T20+5d = 710+338=1048
the answer is t25=79
and it sum of 20th term that is S20=710.
you cannot have the "sum of the 20th term".
If you mean the sum of the 1st 20 terms, then
T10 = a+9d=34
S20 = 10(2a+19d) = 710
so, a=7, d=3
T25 = 7+24*3 = 79