what is the average of the first 200 terms of the series 1,-2,3,-4,5,-6,7....

• average of the first 200 terms of the series 1,-2,3,-4,5,-6,7...
  =1+(-2)+3+(-4)+...+199+(-200)/200
  =(1-2)+(3-4)+(5-6)+...+(199-200)/200
  =(-1)+(-1)+(-1)+...100times/200
  =-100/200
  =-0.5
• 11 years agoHelpfull: Yes(81) No(0)
• 1,3,5.... are in A.P. sum=n/2{(2a+(n-1)d}
  n=100 a=1 d=2 sum= 10000
  on the similar fashion -2,-4.....
  n=100 a=-2 d=-2 sum =-10100
  -10100+10000=-100
  so avg.= -100/200 = -.5
  
• 11 years agoHelpfull: Yes(16) No(0)
• 1+3+5....199=10000
  -2-4-6-8....-200=-10100
  add both of them
  -100
  now avg=-100/200= -1/2 will be ans
• 11 years agoHelpfull: Yes(3) No(0)
• (1+3+5+7+9+-------+199)-(2+4+6+8+---------+200)
  on adding each term we get -100 as the value
  so avg= -100/200=-0.5
• 11 years agoHelpfull: Yes(3) No(0)
• Sum of first N odd numbers: 1,3,5,7...200
  N^2
  N=100=>10000
  Sum of first N even numbers:2,4,6,8,...200
  N^2 + N=>10000+100=>10,100
  so for -2,-4,..-200=>-10,100
  10000-10100=-100;
  Avg=-100/200
  so 0.5
  
• 11 years agoHelpfull: Yes(3) No(0)
• series can be divide into two i,e 1,3,5,7.... and -2,-4,-6....
  so sum of 1st series=10000 and 2nd is -10100
  so total sum=10000-10100=-100
  avg=-100/200=-0.5
• 11 years agoHelpfull: Yes(1) No(2)
• =1+(-2)+3+(-4)+...+199+(-200)/200
  =(1-2)+(3-4)+(5-6)+...+(199-200)/200
  =(-1)+(-1)+(-1)+...100/200
  =-100/200
  =-0.5
• 6 years agoHelpfull: Yes(1) No(0)
• consider two number and add u find only 1
  there are 200 numbers
  all the sum is 100
  to find out average 100/200=0.5
• 11 years agoHelpfull: Yes(0) No(0)
• it is 1-2=-1
  3-4=-1
  .... 100 times
  100 * -1 = -100
  avg -100/200= -1/2
• 11 years agoHelpfull: Yes(0) No(0)
• cause here it provide 1 after each block of (-,+) so 100
• 9 years agoHelpfull: Yes(0) No(0)
• 1,-2,3,-4........ So answer is -0.5
• 8 years agoHelpfull: Yes(0) No(0)
• Average of first 200 terms
  1+(-2)=1-2=-1
  -1+3=2
  2+(-4)=2-4=-2
  -2+5=3
  3+(-6)=3-6=-3
  -3+7=4
  4+(-8)=-4-8=-4
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  100+(-200)=100-200=-100
  So sum of first 200 terms=-100
  Average of first 200 terms=-100/200
  =-0.5
• 8 years agoHelpfull: Yes(0) No(0)
• sum of every 1 pair of no after 1 is 1
  till 200 there are 99 pairs so total sum till 199 terms =100
  the 200th term is -200 as every even no is -ve
  sum till 200 terms=100-200=-100
  avg=-100/200=-0.5
• 7 years agoHelpfull: Yes(0) No(0)
• 10 dssdsdsdsddssds
• 6 years agoHelpfull: Yes(0) No(0)