Out of four numbers ,the average of first three is 16 and that of the last three is 15 .If the last number is 18,the first number is :
A) 20 B) 21 C) 23 D) 25

• let the nos a,b,c,d
  in the 1st condition, a+b+c=48
  in the 2nd condition, b+c+d=45
  
  now,d is given value as 18
  thus, b+c+18=45
  b+c=27
  putting the value of b+c in equation, a+b+c=48
  a+27=48
  a= 21
  
  the answer is 21 (B)
• 12 years agoHelpfull: Yes(13) No(0)
• ans=21
  a,b,c,d
  a+b+c/3=16
  b+c+d/3=15
  d=18
  b+c=45-18=27
  a=16*3-27=21
  
• 11 years agoHelpfull: Yes(2) No(2)
• ANS is 21
  let numbers to be W X Y Z
  (X+Y+Z)/3=15 ,where Z=18
  we will get
  X+Y= 27
  (W+X+Y)/3= 16 , where x+y= 27
  we will get
  W = 21
• 7 years agoHelpfull: Yes(2) No(0)
• a+b+c=48...........(i)
  b+c+d=45...........(ii)
  b+c=45-18=27
  a=48-27=21
  so ans is 21
• 10 years agoHelpfull: Yes(1) No(2)
• the answer is 21
  
• 9 years agoHelpfull: Yes(1) No(0)