Question

1+2+3+...........+50=?

Answer 1

Let a be the first term, d common difference and l the last term.
a=1, d=2-1=3-2=1 (*the given nos are in ap;so common difference. ) , l=50

Therefore Sn=n/2(a+l)

S50=50/2(1+50)

=25*51=1275... (ans)

Answer 2

☺☺ HEYA FRIENDS ☺☺

I think you want the sum of given series.

a=1
d=2-1=1
Tn=50

Tn = a+(n-1)d
50 = 1+(n-1)1
49 = n-1
n = 50

Sn = n/2[2a+(n-1)d]
=50/2[2(1)+(50-1)1]
=25[2+49]
=25×51
=1275

HOPE IT HELPS YOU☺☺