Answers

2014-10-31T22:06:24+05:30
We can make groups of two to make this EQ. shorter 

1-2=-1      3-4=-1    ............   79-80=-1 

therefore answer should be -40 because we made 40 pairs as such

ANS=>    -40
hope this will help you 
Reguards
Vishwas Choudhary

0