The sum of 5 numbers in AP is 30 and the sum of their square is 220.
Which of the following is the third term ?

1) 5
2) 6
3) 8
4) 9

• answer can be easily found in this way-
  5 terms of an A.P can be represented in the form as a-2d,a-d,a,a+d,a+2d.
  then sum = a-2d + a-d + a + a+2d +a+d that is 30
  so after addind a = 6.
  that is answer
• 9 years agoHelpfull: Yes(35) No(4)
• We have to find the third term. To do so, the formula for nth term in a series is : a + (n-1)d
  So, for the third term, substitute n = 3 in the above formula, you get : a + 2d (This is what we need to find)
  Now, according to the given question :
  Sum of 5 numbers of an AP = 30
  So, using the formula n/2(2a + (n-1)d) = 30
  Solve the above equation, you get a + 2d = 6
  Which is our required answer.
• 9 years agoHelpfull: Yes(26) No(1)
• 2+4+6+8+10=30
  4+16+36+64+100=220
• 9 years agoHelpfull: Yes(15) No(6)
• let the no be a-2d,a-d,a,a+d,a+2d
  sum of a-2d+a-d+a+a+d+a+2d=30
  5a=30 =>a=6
  sum their squares (a-2d)^2+(a-d)^2+a^2+(a+d)^2+(a+2d)^2=220
  180+10d^2=220
  10d^2=40
  d=2
  so the nos are 2,4,6,8,10
  the third term is 6
  ANS=6
• 9 years agoHelpfull: Yes(8) No(0)
• x+2x+3x+4x+5x=30
  15x=30
  x=2
  sub x value in 3rd term so the answer will be 6
• 9 years agoHelpfull: Yes(6) No(0)
• 5/2(2a+4d)=30 ; a+2d=6 Therefore a=2 and d=2 (only possible combination ).
  third term is 6
• 9 years agoHelpfull: Yes(1) No(0)
• Let the 5 no which are in ap as
  A-2d A-d A A+d A+2d
  Sum is 30 so 5A = 30
  A= 6 which is 3rd no
• 8 years agoHelpfull: Yes(1) No(0)
• ans will be 6..
  
  
• 9 years agoHelpfull: Yes(0) No(0)
• 3rd trm will be 6
• 9 years agoHelpfull: Yes(0) No(0)
• let the terms are a-5d,a-3d,a,a+3d,a+5d
  sum =>5a=30
  =>a=6
  therefore 3rd term is 6
• 8 years agoHelpfull: Yes(0) No(0)
• Sn=n/2[2a+(n-1)d]
  S5=5/2[2a+4d]=30
  2a+4d=12
  a+2d=6 which is the third term
  
• 8 years agoHelpfull: Yes(0) No(0)
• consider a,a+d,a+2d,a+3d,a+4d are 5 numbers in ap
  given the sum that 30 we know when sum is given the formula is n/2(2a+(n-1)d)
  
  n/2(2a+(n-1)d)=30
  5/2(2a+4d)=30
  2a+4d=12
  a+2d=6
  in the above series a+2d is the third term so the third term is equal to 6
  so answer is 2)6
• 8 years agoHelpfull: Yes(0) No(0)
• a,a+d,a+2d,a+3d,a+4d=30
  mean=a+2d=30/5
  3rd term=6
• 7 years agoHelpfull: Yes(0) No(0)