Amal bought 5 pens, 7 pencils and 4 erasers. Rajan bought 6 pens, 8 erasers and 14 pencils for an amount which was half more than what Amal had paid. What % of the total amount paid by Amal was paid for pens?

• 62.5%
  assume amal's amount=100
  5x+7y+4z=100 and 6x+14y+8z=150
  solving this get x=12.5% ............... 5 pens ->5*12.5->62.5%
• 13 years agoHelpfull: Yes(37) No(12)
• let p be no of pens
  let b be no of pencils
  let e be no of eraser
  let x be the amount paid by amal
  so the eqn becomes..5p+7b+4e=x;6p+14b+8e=3x/2;
  if you observe the symmetry in the eqn ie.7b+4e and 14b+8e so we can rearrange the eqn 1 and 2 and multiplying eqn1 by 2 we get
  14b+8e=2(x-5p);
  14b+8e=3x/2-6p
  now equating both eqn,we get
  2x-10p=3x/2-6p
  x/2=4p
  x=8p
  p=100x/8(bcoz it's asked in terms of % )
  p=12.5% of x
  ans=12.5%
  
• 13 years agoHelpfull: Yes(16) No(5)
• how can u solve two equations having 3 variables?
  u need to have 3 equations,isnt it?
• 13 years agoHelpfull: Yes(8) No(13)
• answer is 80%..
• 13 years agoHelpfull: Yes(2) No(15)
• Let, 5 pens + 7 pencils + 4 erasers = x rupees
  so 10 pens + 14 pencils + 8 erasers = 2*x rupees
  also mentioned, 6 pens + 14 pencils + 8 erarsers = 1.5*x rupees
  so (106)
  = 4 pens = (21.5)
  x rupees
  so 4 pens = 0.5x rupees => 8 pens = x rupees
  so 5 pens = 5x/8 rupees = 5/8 of total (note x rupees is total amt paid byamal)
  i.e 5/8 = 500/8% = 62.5% is the answer
• 9 years agoHelpfull: Yes(1) No(0)