A certain type of mixture is prepared by mixing brand A at Rs.9 a kg. with brand B at Rs.4 a kg. If the mixture is worth Rs.7 a kg., how many kgs. of brand A are needed to make 40kgs. of the mixture?

• the ratio of brand A and B in the mixture i 3:2
  so the quantity of brand A is =3*40/5=24
  24 kg of brand A needed to make the 40 kg mixture
• 10 years agoHelpfull: Yes(11) No(3)
• A + B = 40.
  
  And at Rs 7 a kg for 40 kg, you want a total of Rs.280.
  
  So the second equation is 9A + 4B = 280
  
  From the first equation: B = 40 - A
  and sub into the second equation:
  
  9A + 4(40-A) = 280
  9A + 160 - 4A = 280
  5A = 120
  A = 24.
  
  And you should check: B should equal 40-24 = 16. Check with the final equation: 9*24 + 4*16 = 216 + 64 = 280. So it works.
  
  Your answer, of course, is A = 24.
• 10 years agoHelpfull: Yes(9) No(2)