3. (209*144)^2 + (209*209)+(209*144)+(144*144) = ? a)905863729 b)905368729 c)905729368 d)65

• Answer will be a)905863729 by digit sum method
  
• 9 years agoHelpfull: Yes(16) No(10)
• consider 209=a,144=b
  (ab)^2+(a)^2+ab+b^2 add -ab +ab then (a+b)^2+ab(ab-1)
  solving we get 905868729
• 9 years agoHelpfull: Yes(8) No(4)
• Since 3 solutions have same digit arrangement so digit can be applied.
  go for unit digit approach will get 9 so. either a) or b) then calculate the highest product that is (209*144)^2
• 9 years agoHelpfull: Yes(2) No(3)
• hi tapas..
  by using digit sum method we are getting the same value for option b & option c i.e. 4
• 9 years agoHelpfull: Yes(2) No(2)
• Hello tapas,
  please explain the digit sum method for this question.
  Thanks
  
• 9 years agoHelpfull: Yes(2) No(0)
• please explain the method
• 9 years agoHelpfull: Yes(1) No(0)
• aftr multiply all we get 905863729
• 9 years agoHelpfull: Yes(0) No(4)