Solution: Given sum of 10n-1=3798 by this we can find first term 10n-1 put n=1 we get 9 second term put n=2 we get 19 a=9 d=second term-first term d=10 Sn=3798 by AP we have Sn=[2a+(n-1)d] 3798=[2*9+(n-1)10] 3798=[18+10n-10] 3798=[8+10n] n=379 there for the nth term is 379.