Average of seven nos is 25. avg of first three of them is 35 while last three of
them is 20.

• Middle number is 10.
  
  Average of seven no. is 25 ==> 25*7 = 175
  First three number is 35 ==> 35*3 = 105
  Last three number is 20 ==> 20*3 = 60
  
  Middle number is = Total + (total of first 3num +total of last 3num)
  = 175 - (105+60)
  = 175 - 165
  = 10
• 12 years agoHelpfull: Yes(21) No(0)
• avg of 7 numbers is 25 then sum of 7 nos is 175 . avg of first 3 nos is 35 then sum of first 3 nos is 105. avg of last 3 nos is 20 then sum of last 3 nos is 60. 105+x+60=175
  x=10
• 10 years agoHelpfull: Yes(1) No(0)