Question

Sum of the series is 31+29+27..... +7. with explanation pls

Answer 1

Answer:

see difference between 31 &29 is 2 as well as difference between 29 &27 is 2 ...

therefore 27-2=25...

25-2=23..

23-2=21...

21-2=19

19-2=17

17-2=15..

15-2=13..

13-2=11..

11-2=9..

9-2=7..

now addition of this no.

31+29+27+25+23+21+19+17+15+13+11+9+7=247...

or u can even solve by A.P.....