Of a set of 30 numbers, average of first 10 numbers = average of last 20 numbers. Then the sum of the last 20 numbers is ?
(a)2 X sum of first ten numbers
(b)2 X sum of last ten numbers
(c)Sum of first ten numbers
(d)Cannot be determined with given data

• since, average=(sum of n no.s)/(total no)
  therefore, (sum of first 10 no.s)/10 ==(sum of last 20 no)/20
  hence. (sum of last 20 no.s) = 2*(sum of first 10 no.s)
  
• 11 years agoHelpfull: Yes(71) No(0)
• option a
  twice the sum of first ten numbers.......
• 11 years agoHelpfull: Yes(19) No(0)
• a)2xsum of first ten numbers
  sum of first 10 numbers be a
  sum of last 20 numbers be b
  avg of first 10 nos =avg of last 20 nos
  i.e (a/10)=(b/20)
  (20 x a)/10 = b
  2a=b
  therefore 2 x sum of first ten numbers = sum of last 20 numbers
• 11 years agoHelpfull: Yes(7) No(0)
• 2*sum of first ten numbers..
• 11 years agoHelpfull: Yes(2) No(1)
• average of first 10 number = (x1+x2+x3-------+x10)/10
  average of last 20 number = (x11+x12+--------+x30)/20
  (x1+x2+x3-------+x10)=(x11+x12+--------+x30)/2
  (x11+x12+--------+x30)=2*(x1+x2+x3-------+x10)
  i.e the sum of the last 20 numbers = 2*(the sum of the first 10 numbers)
• 8 years agoHelpfull: Yes(2) No(0)
• option c....
  Sum of first ten numbers
• 11 years agoHelpfull: Yes(1) No(17)
• (x1+........+x10)/10=(x11+..............+x30)/20
  so (x11+.....+x30)=2*(x1+......+x10)
  so option will be (a)
• 8 years agoHelpfull: Yes(1) No(1)
• a as avg of first 10 and last 10 numbers will be the same
• 11 years agoHelpfull: Yes(0) No(4)
• a) 2 times sum of first ten numbers !!!
• 11 years agoHelpfull: Yes(0) No(2)
• 2*(sum of 1st ten member)
  
• 10 years agoHelpfull: Yes(0) No(0)
• a,2xsum of last ten numbers
• 9 years agoHelpfull: Yes(0) No(0)
• (x1+-----x10)/10=(x11_____x30)/20
  
• 9 years agoHelpfull: Yes(0) No(0)
• 2Xsum of first ten numbers
• 9 years agoHelpfull: Yes(0) No(0)
• answer=(a).
• 9 years agoHelpfull: Yes(0) No(0)
• Let average of first 10 numbers is a. Then sum = 10a
  Average of last 20 nmbers also a. Then their sum = 20a
  From the options a is correct
• 8 years agoHelpfull: Yes(0) No(0)
• cheppanu brother.meere cheskondi
• 7 years agoHelpfull: Yes(0) No(0)
• a)2 X sum of first ten numbers
• 6 years agoHelpfull: Yes(0) No(0)
• a
  sum of first ten/10=sum of last twenty/20
  therefore,sum of last twenty=2 X sum of first ten
• 6 years agoHelpfull: Yes(0) No(0)