The average of 7 numbers is 50. The average of first three of them is 40, while the average of the last three is 60. What must be the remaining number?

• The answer is 50.
  Consider a,b,c,d,e,f,g are the seven numbers.
  Given, (a+b+c+d+e+f+g)/7= 50 which is eqn1. , (a+b+c)/3=40 which means a+b+c=120, and (e+f+g)/3=60 which means e+f+g=180.
  Using both the values in eqn1 we get 120+d+180=(50*7)
  d+300=350 which implies d=50.
• 9 years agoHelpfull: Yes(29) No(1)
• sum of 7 numbers= 7*50= 350
  sum of first 3 numbers= 3*40= 120
  sum of last 3 numbers= 3*60= 180
  let the left no. be x
  350= 120+180+x
  x= 50
  ans is 50
• 9 years agoHelpfull: Yes(13) No(2)
• 50
  sum of first 3 no=40*3=120
  sum of last 3=60*3=180
  third no=350-300=50
• 9 years agoHelpfull: Yes(5) No(2)
• A+B+C+D+E+F+G=350,
  A+B+C=120,
  E+F+G=180
  HENCE, D=50
  
• 9 years agoHelpfull: Yes(4) No(1)
• remaining number is total sum-(sum of first three and last three)
  i.e> 7*50-(3*40+3*60)=350-300
  50
• 9 years agoHelpfull: Yes(2) No(0)
• 7*50=(40*3)+(60*3)+x
  x=50
• 9 years agoHelpfull: Yes(2) No(0)
• 50
  7*50=350;
  3*40=120;
  3*60=180;
  350=120+180+x
  x=50
  
• 9 years agoHelpfull: Yes(2) No(0)
• ans will be 50
• 9 years agoHelpfull: Yes(2) No(0)
• x1+x2+x3+x4+x3+x6+x7=7*50
  x1+x2+x3=40*3
  x7+x6+x5=60*3
  120+x4+180=350
  x4=350-300
  x4=50
• 9 years agoHelpfull: Yes(1) No(0)
• 7 members total=350////avg=50.
  3 ". Total=120//avg=40.
  Last 3 members total180//avg=60.
  Then 350-300=50
• 9 years agoHelpfull: Yes(1) No(0)
• 50
  x=350-(300)
• 9 years agoHelpfull: Yes(1) No(0)
• avg=50
  total no=7
  avg=sum/total no;
  so, 50=(3(40) + x + 3(60)) / 7 ;
  solve for x..
  x=50;
  is the answer....
  
• 9 years agoHelpfull: Yes(1) No(0)
• total sum of 7 nos=7*50=350
  sum of first 3 nos=3*30=120
  sum of last 3 nos= 3*60=180
  fourth number=total sum of 7 nos-(sum of first 3 nos+sum of last 3 nos)
  =350-(120+180)=50
• 9 years agoHelpfull: Yes(1) No(0)
• 350-300=50
• 9 years agoHelpfull: Yes(0) No(0)
• sum of 7 numbers=7*50=350
  sum of x1,x2,x3=120
  similarly sum of x4,x5,x6=180
  so x7=350-120-180=50
• 9 years agoHelpfull: Yes(0) No(0)
• a+b+c+d+e+f+g=350;
  a+b+c=120;
  e+f+g=180;
  then d=350-300=50
  
• 9 years agoHelpfull: Yes(0) No(0)
• 35,40,45,50,55,60,65 are numbers
• 9 years agoHelpfull: Yes(0) No(0)
• 7*50=3*40+x+3*60
  x=350-(120+180)
  x=50
• 8 years agoHelpfull: Yes(0) No(0)
• Suppose that:-
  7 numbers be:- A,B,C,D,E,F,G
  NOW,
  The average formula is :- average = Sum of items/total number of items
  so average of 7 numbers given above is 50
  A+B+C+D+E+F+G/7 = 50
  ans will be 350 assume it as equation 1
  now given
  first three numbers have average of 40 and last three have average of 60
  take out value of A+B+C and E+F+G i.e 120 and 180 respectively
  put them in equation 1 as assumed earlier
  take out value of d i.e 50
  hence 50 will be answer
  
• 7 years agoHelpfull: Yes(0) No(1)
• answer is 50.
• 7 years agoHelpfull: Yes(0) No(0)
• avg of frst 3 is 40 and that of last 3 is 60 so 100 and 3+3=6 so d remains hence 100-50=50.
• 5 years agoHelpfull: Yes(0) No(0)
• the answer is 58
• 4 years agoHelpfull: Yes(0) No(0)