The number of common terms in the two sequences 17,21,25,…,417 and 16,21,26,…,466 is
a) 78
b) 19
c) 20
d) 77

• first common term is 21, now the next common term will have a common difference that is the LCM of the common differences of both aps.
  
  Here it is 4*5 = 20
  
  Hence the series of common terms is 21,41,61, and so on
  
  now for the last term it has to be 401.
  
  Hence no of common terms is 401 = 21 + (n-1)20
  
  380/20 = n-1
  n=20
  
  
  
  
  
• 10 years agoHelpfull: Yes(6) No(0)
• 1st sequencely 25,29,33,37,41,45,49,53,57,61,65,69,73,77.(each distance is 3).
  2nd sequencely 26,31,36,41,46,51,56,61,66,71,76.option is 77
• 10 years agoHelpfull: Yes(0) No(1)
• plz explain how 77 is the answer
• 10 years agoHelpfull: Yes(0) No(1)
• 21,41,61,81,101,121,141,161,181,201,221,241,261,281,301,321,341,361,381,401,421,441,461, the common numbers for the above series are 20 like common terms , the total numbers in common are 23 oly.
  explanation 17 start series numbers are difference of 4 and 16 start series difference of 5. in this two series the above numbers were common
• 10 years agoHelpfull: Yes(0) No(0)