Question 399675
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Hi, The sum of the ages of a brother and sister is 27
Let x and (27-x))represent the sister's and brother's ages respectively
Question states***
 3x - 4(27-x)= 11
Solving for x
 3x + 4x - 108 = 11
  7x = 119
   x = 17, the sister's age.  The brother is 10   (27-17)
 
CHECKING our Answer***
  3*17 - 4*10 = 51 - 40 = 11