In a 4- digit number, the sum of the first two digits is equal to that of the last two digits. The sum of the first and last digits is equal to the third digit. Finally, the sum of the second and fourth digits is twice the sum of the other two digits.What is the third digit of the number?

• 5 is the third digit.
  
  Let,
  1st digit = A
  2nd digit = B
  3rd digit = C
  4th digit = D;
  
  Conditions:
  
  A+B = C+D
  A+D = C
  B+D = 2(A+C)
  
  A=1; B=8; C=5; D=4; Which satisfies all the conditions.
• 12 years agoHelpfull: Yes(7) No(2)
• 5 is the third digit.
  
  Four digit number = 1854
  
  Conditions :
  
  Sum of the first two digits(1+8) = Sum of the last two digits (5+4)
  Sum of the first and last digits (1+4) = Third digit (5)
  Sum of the second and fourth digits (8+4)= Twice the sum of the other two digits [2(1+5)]
  
• 12 years agoHelpfull: Yes(3) No(0)