the ratio of the ages ofA and B seven years ago was 3:4.the ratio of their ages nine years from now will be 7:8.what is B's age present ar present?

• Let x and y be the present ages of A and B respectively.
  Then according to what is given,(x-7)/(y-7)=3/4 and (x+9)/(y+9)=7/8
  On simplifying we get, 4x-3y = 7 ....(1) and 8x-7y = -9 ....(2)
  Multiplying (1) by 2,we get 8x-6y = 14 ....(3)
  Now subtracting 2 from 3 we get -6y+7y=23.
  y=23 which is the present age of B
• 11 years agoHelpfull: Yes(3) No(0)
• Ans:A- 19, B- 23
  Solution: (3x+16)/(4x+16)= 7/8
  x= 4.
  A= 3*4+7=19
  B = 4*4+7 =23
• 11 years agoHelpfull: Yes(2) No(1)
• (A - 7) / (B - 7) = 3 / 4
  => 4A - 28 = 3B - 21
  => 4A - 3B = 7 -------(2)
  
  (A - 9) / (B - 9) = 7/8
  => 8A - 72 = 7B - 63
  => 8A - 7B = 9 -------(1)
  
  Solving 1 and 2,
  present age of B = 5
• 11 years agoHelpfull: Yes(0) No(2)
• let the current ages of a and b are x & y.
  before 7 yrs their age ratio was 3:4
  =>x-7/y-7=3/4 =>4x-3y=7
  and after 9 yrs their age ratio will be 7:8
  => x+9/y+9=7/8 => 8x-7y=-9
  now solve both the equation
  we get,
  x=19 and y=23
• 11 years agoHelpfull: Yes(0) No(0)