5) Arithmetic series is typically: a, a+d, a+2d, ..., a+(n-1)d, ... where n indicates Tn and d is the common difference, a is the first term.
Therefore, T4=a+3d=22 and T9=a+8d=32. T9-T4=5d=10, d=2, a=T4-3d=22-6=16.
Series is 16, 18, 20, 22, 24, 26, 28, 30, 32, ... so T8=30.
Using the formula a+(n-1)d we also get 16+7×2=30 for T8.
S10=16+18+20+22+24+26+28+30+32+34=
(16+34)+(18+32)+(20+30)+(22+28)+(24+26)=
5×50=250.
We can also use the formula (n/2)(2a+(n-1)d)=(10/2)(32+18)=250 for S10.