The sum of odd number between 20 and 30 is

(a) 125
(b) 140
(c) 120
(d) 105

• a=21,l=29 Clearly n=5;
  sum=n(a+l)/2=5*(21+29)/2;
  Ans:125
• 8 years agoHelpfull: Yes(18) No(2)
• ans is a.
  that is,21+23+25+27+29=125
• 8 years agoHelpfull: Yes(8) No(0)
• between 20 to 30 there is 5 consecutive odd numbers i.e.
  21 23 25 27 29.
  clearly average of these 5 numbers 25.
  so sum will be 25*5=125 (ans. a)
• 8 years agoHelpfull: Yes(6) No(0)
• a,21+23+25+27+29=125
• 8 years agoHelpfull: Yes(0) No(0)
• 125
  logic: add all odd numbr b/w 20 2 30
  
• 8 years agoHelpfull: Yes(0) No(0)
• 125 is the answer
  odd nos betw 20 and 30 : 21,23,25,27,29
  it's in AP series.
  so, a=21, n=5,d=2
  s=n/2[a+(n-1)d]
  =125
• 8 years agoHelpfull: Yes(0) No(0)
• odds no.s between 20-30 are 21,23,25,27,29 and their sum equals to 125.
  So,option a is correct.
• 8 years agoHelpfull: Yes(0) No(0)
• The odd nos between 20 to 30 are from 21+23+......... +29 that is total number of odd numbers=29-21=8.
  8/2+1=5=n
  Sum of odd nos=5/2*(20+30)=125
• 8 years agoHelpfull: Yes(0) No(0)
• 21+23+25+27+29=125
• 8 years agoHelpfull: Yes(0) No(0)
• 21+23+25+27+29=125
• 6 years agoHelpfull: Yes(0) No(0)
• 125
  
  21+23+25+27+29=125
• 5 years agoHelpfull: Yes(0) No(0)