Urgent math question

• blowfish

  3 Oct 07, 16:42

  The ratio of the number of red counters to the number of blue counters in a box is 7:3. If 36red counters are removed and 24blue counters added, there will be an equal numbers of red counters and blue counters.
  how many red counters are there in the box?
  
  what the answer?
• tut4nkh4m3n

  3 Oct 07, 16:47

  wa sian i dunno
• tut4nkh4m3n

  3 Oct 07, 16:51

  ohh i got it!
  
  red - 105
  blue - 45
  
  muhahaha!
• Phoebie

  3 Oct 07, 16:51

  Originally posted by blowfish:

  The ratio of the number of red counters to the number of blue counters in a box is 7:3. If 36red counters are removed and 24blue counters added, there will be an equal numbers of red counters and blue counters.
  how many red counters are there in the box?
  
  what the answer?

  let me try
  
  red : blue
  7 : 3
  
  red 7 units, blue 3 units
  7 - 3 = 4 units excess
  
  36 + 24 = 60
  60 / 4 = 15
  15 x 7 = 105
  
  105?
• shinta

  3 Oct 07, 16:52

  Originally posted by blowfish:

  The ratio of the number of red counters to the number of blue counters in a box is 7:3. If 36red counters are removed and 24blue counters added, there will be an equal numbers of red counters and blue counters.
  how many red counters are there in the box?
  
  what the answer?

  hw many now or before?
• shinta

  3 Oct 07, 16:52

  105 before 69 after?
• potteram

  3 Oct 07, 16:54

  Let Number of red counters be X.
  Let Number of blue counters be Y.
  
  ratio of red counters and blue counters: X/7 = Y/3 ----(1)
  
  If 36red counters are removed and 24blue counters added, there will be an equal numbers of red counters and blue counters:
  
  X - 36 = Y + 24 -----(2)
  
  (1): 3X - 7Y = 0
  (2): X - Y = 60 --------> 3X - 3Y = 180
  
  Sub (2) into (1):
  
  (180 + 3Y) - 7Y = 0
  
  4Y = 180
  Y = 45
  
  Sub Y=45 into (2):
  ==> X - 45 = 60
  ==> X = 105
  
  
• shinta

  3 Oct 07, 16:56

  Originally posted by potteram:

  Let Number of red counters be X.
  Let Number of blue counters be Y.
  
  ratio of red counters and blue counters: X/7 = Y/3 ----(1)
  
  If 36red counters are removed and 24blue counters added, there will be an equal numbers of red counters and blue counters:
  
  X - 36 = Y + 24 -----(2)
  
  (1): 3X - 7Y = 0
  (2): X - Y = 60 --------> 3X - 3Y = 180
  
  Sub (2) into (1):
  
  (180 + 3Y) - 7Y = 0
  
  4Y = 180
  Y = 45
  
  Sub Y=45 into (2):
  ==> X - 45 = 60
  ==> X = 105
  
  

  my version easier..
  
  draw a model... 7 units for red, 3 for blue..
  
  4 units = 36+ 24
  
  frm there count
• eagle

  3 Oct 07, 16:58

  yep is 105
• tut4nkh4m3n

  3 Oct 07, 16:59

  what standard huh this qn?
• potteram

  3 Oct 07, 17:00

  Originally posted by Phoebie:

  let me try
  
  red : blue
  7 : 3
  
  red 7 units, blue 3 units
  7 - 3 = 4 units excess
  
  36 + 24 = 60
  60 / 4 = 15
  15 x 7 = 105
  
  105?

  errr i dun think you calculate like that one leh........ =/
  even though your answer is not wrong.
• Phoebie

  3 Oct 07, 17:04

  Originally posted by tut4nkh4m3n:

  what standard huh this qn?

  i think primary 5 or primary 6
  
  recalled doing such sums in pri 5 / 6
• eagle

  3 Oct 07, 17:05

  Originally posted by potteram:

  errr i dun think you calculate like that one leh........ =/
  even though your answer is not wrong.

  the reasoning looks correct to me
• Phoebie

  3 Oct 07, 17:07

  Originally posted by potteram:

  errr i dun think you calculate like that one leh........ =/
  even though your answer is not wrong.

  i draw models that's why i calculate this way
• eagle

  3 Oct 07, 17:10

  Sometimes presentation of solutions are important. It depends which level you are at, and what the teacher wants. Since TS didn't state his level, we can just assume the easiest way for him
• shinta

  3 Oct 07, 17:10

  Originally posted by Phoebie:

  i draw models that's why i calculate this way

  ^5
  
  
• tut4nkh4m3n

  3 Oct 07, 17:11

  Originally posted by Phoebie:

  i think primary 5 or primary 6
  
  recalled doing such sums in pri 5 / 6

  i dont rmbr standard being so high
  
  hmmm
• Phoebie

  3 Oct 07, 17:13

  Originally posted by shinta:

  ^5
  
  

  five
• hiphop2009

  4 Oct 07, 11:44

  aiyah, draw all the boxes out lo...
  
  i rmb last time got one qns in pri sch.
  
  wad is 1+2+3........+99+100 =?
  
  pri sch no calculator, so i really calculate everything one by one......
• wishboy

  4 Oct 07, 20:31

  1+2+3+........+99+100
  = (100+1)*50
  = 5050
• 798

  4 Oct 07, 20:37

  Originally posted by Phoebie:

  let me try
  
  red : blue
  7 : 3
  
  red 7 units, blue 3 units
  7 - 3 = 4 units excess
  
  36 + 24 = 60
  60 / 4 = 15
  15 x 7 = 105
  
  105?

  phoebie so smart!
  
  i bet none of us nvr think of using ur method to calculate.
• eagle

  4 Oct 07, 22:25

  Originally posted by 798:

  phoebie so smart!
  
  i bet none of us nvr think of using ur method to calculate.

  
• HyuugaNeji

  4 Oct 07, 22:37

  Originally posted by blowfish:

  The ratio of the number of red counters to the number of blue counters in a box is 7:3. If 36red counters are removed and 24blue counters added, there will be an equal numbers of red counters and blue counters.
  how many red counters are there in the box?
  
  what the answer?

  7x-36=3x+24
  4x=60
  x=15
  
  original red: 15*7=105
  
  
• ^tamago^

  4 Oct 07, 22:43

  What level?
• Phoebie

  6 Oct 07, 03:18

  Originally posted by 798:

  phoebie so smart!
  
  i bet none of us nvr think of using ur method to calculate.

  
  
  hi 798