Question

.the sum of 10 terms of the arithmetic series is 390. of the third term of the series is 19. find the first term

Answer 1

Its a easy question dear:-
just make two equation and solve it:-

sum:- n/2{2a+(n-1)d}
=>10/2(2a+9d)
=>10a+45d = 390
=> 2a+9d=78---------------(1)

now
a+(n-1)d =19
=> a+2d=19-------------(2)

now (1)-2(2)
=>5d=40
=>d=8

so a = 3

Answer 2

So the a value is 3.