First we increased the denominator of a positive fraction by 3 and then we decreased it by 5. The sum of the resulting fractions proves to be equal to 19/42. Find the denominator of the fraction if the numerator is 2
A.
7
B.
8
C.
12
D.
9

• D.9
  
  initially the fraction will be 2/x
  
  then we increase the denominator by 3
  
  the fraction will become 2/x+3
  
  now we decrease the denominator by 5
  
  the new fraction will be
  
  2/x-2
  
  accn to ques. {2/x+3}+{2/x-2}=19/42
  
  on solving the epressions we will get an eqn.
  
  19x^2-149-198=0
  
  in solving the eqn. we get x=9
• 9 years agoHelpfull: Yes(15) No(2)
• C
  from options we can check.
• 9 years agoHelpfull: Yes(1) No(5)
• Ans is option D : 9
  
  Solution go with the answer options
  
  since we see 42 in denominator of sum,that means either the lcm of two changed fraction is 42 or a multiple of 42.
  
  For 7, we would have 7+3 * 10-5 that is 50, so we can never have 42 as denominator,with a quick and sharp observation we see having 9 as denominator of the fraction we would have 9+3 * 12-5 = 84 which is multiple of 42 and must have 38 in the numerator and got divided by 2 resulting 42.
  
  
• 7 years agoHelpfull: Yes(0) No(0)