Question

Sum of all numbers lying number between 250 and 1000 exactly divisible by 3 is

Answer 1

Hey mate,
here ur answer.......

The numbers lying between 250 and 1000 exactly divisible by 3 are...
252,255,258,......................996.
Here a=252 , common difference,d=255-252=3
n th term i.e.,an=996.
W.K.T, an=a+(n-1)d
996=252+(n-1)3
996-252=3n-3
744+3=3n
n=249

W.K.T, Sn=n/2[2a+(n-1)d]
Sn=249/2[2(252)+(249-1)3]
=249/2(504+744)
=249/2(1248)
Sn=155376
Hope it will help u.
plz mark it as brainlest.