A primary maths question I can't solve...

• newcomer

  5 Apr 06, 23:06

  Mr Koh's salary to that of his wife is in the ratio 4:3. Each of them saves $246 and spends the rest of their money. If Mr Koh's expenditure to that of his wife is in the ratio 18:13, find their total salaries.
  
  Any help would be much appreciated.
  
  P.S: Kind of embarrassed to not able to solve this qns for my little cousin.
• newcomer

  5 Apr 06, 23:13

  Onegai!
• DeathEdge

  5 Apr 06, 23:15

  Hmm im damn noob to primary sch maths but maybe u try to make 18:13 into 4:3 by adding units into it.. agar agar u should get 20:15 by adding 2 to each side.. so 2 unit = $246 ; 1 unit = $123.. so total 20+15 unit = 35 unit = 35 x 123 = $4305.. if wrong dont find me coz.. i said le im noob to primary sch maths =x
• Qing^.^

  5 Apr 06, 23:16

  eh u sure primary maths ma? so difficult
• newcomer

  5 Apr 06, 23:20

  Originally posted by Qing^.^:

  eh u sure primary maths ma? so difficult

  That's what I asked her! Got 2 other questions also and although I managed to solve it, it took me quite some time! The method I used they oso haven't learnt lor. Wl eh, now primary school standard damn high man.
• Qing^.^

  5 Apr 06, 23:21

  Originally posted by DeathEdge:

  Hmm im damn noob to primary sch maths but maybe u try to make 18:13 into 4:3 by adding units into it.. agar agar u should get 20:15 by adding 2 to each side.. so 2 unit = $246 ; 1 unit = $123.. so total 20+15 unit = 35 unit = 35 x 123 = $4305.. if wrong dont find me coz.. i said le im noob to primary sch maths =x

  U are smart.. mayb i shld say i stupid but i really duno
• Qing^.^

  5 Apr 06, 23:23

  Originally posted by newcomer:

  That's what I asked her! Got 2 other questions also and although I managed to solve it, it took me quite some time! The method I used they oso haven't learnt lor. Wl eh, now primary school standard damn high man.

  Sooo sooo high lor..
• newcomer

  5 Apr 06, 23:23

  Originally posted by DeathEdge:

  Hmm im damn noob to primary sch maths but maybe u try to make 18:13 into 4:3 by adding units into it.. agar agar u should get 20:15 by adding 2 to each side.. so 2 unit = $246 ; 1 unit = $123.. so total 20+15 unit = 35 unit = 35 x 123 = $4305.. if wrong dont find me coz.. i said le im noob to primary sch maths =x

  It's wrong lor...
• Ecxentrique

  5 Apr 06, 23:27

  Originally posted by newcomer:

  Mr Koh's salary to that of his wife is in the ratio 4:3. Each of them saves $246 and spends the rest of their money. If Mr Koh's expenditure to that of his wife is in the ratio 18:13, find their total salaries.
  
  Any help would be much appreciated.
  
  P.S: Kind of embarrassed to not able to solve this qns for my little cousin.

  if cant use algebra..
  
  the ratio salaries have to be multiplied by 5 to become 20:15
  and expense ratio = 18:13
  
  have to find the savings ratio..
  
  hence salary ratios - expenses ratio = (20-18 ) : ( 15-13) = 2:2
  
  hence savings ratio is the same.. i.e. 246= 2 units of the expense ratio
  
  total salaries have to take (20+15)*246/2 = (35)*123 = 4305..
• DeathEdge

  5 Apr 06, 23:28

  Originally posted by Ecxentrique:

  if cant use algebra..
  
  the ratio salaries have to be multiplied by 5 to become 20:15
  and expense ratio = 18:13
  
  have to find the savings ratio..
  
  hence salary ratios - expenses ratio = (20-115-13) = 2:2
  
  hence savings ratio is the same.. i.e. 246= 2 units of the expense ratio
  
  total salaries have to take (20+15)*146/2 = (35)*73 = 2555..

  eh how come the last part is *146/2??
• newcomer

  5 Apr 06, 23:29

  Originally posted by Ecxentrique:

  if cant use algebra..
  
  the ratio salaries have to be multiplied by 5 to become 20:15
  and expense ratio = 18:13
  
  have to find the savings ratio..
  
  hence salary ratios - expenses ratio = (20-18 ) : ( 15-13) = 2:2
  
  hence savings ratio is the same.. i.e. 246= 2 units of the expense ratio
  
  total salaries have to take (20+15)*146/2 = (35)*73 = 2555..

  Wow you're a genius! Do you teach maths?
• Ecxentrique

  5 Apr 06, 23:30

  Originally posted by DeathEdge:

  eh how come the last part is *146/2??

  mistake on my part.. corrected..
• Ecxentrique

  5 Apr 06, 23:31

  Originally posted by newcomer:

  Wow you're a genius! Do you teach maths?

  pls see if the revised answer is correct.. used to teach my sis such stuff also..
• DeathEdge

  5 Apr 06, 23:31

  Originally posted by Ecxentrique:

  mistake on my part.. corrected..

  pai seh.. c0ck eye
• Ecxentrique

  5 Apr 06, 23:33

  Originally posted by DeathEdge:

  eh but 246/2 become 73 that part haven corrected leh..

  getting old.. haha and brain clsoing shop liao..
  
  should be 4305.. but the answer has been disputed leh.. strange..
• newcomer

  5 Apr 06, 23:34

  
  hence salary ratios - expenses ratio = (20-18 ) : ( 15-13) = 2:2
  
  hence savings ratio is the same.. i.e. 246= 2 units of the expense ratio
  
  total salaries

  Why is 246 = 2 units of the expense ratio? Why not salary ratio?
• DeathEdge

  5 Apr 06, 23:34

  ya lor.. i do backwards and it works fine leh.. think the bk answer wrong.
• Ecxentrique

  5 Apr 06, 23:35

  Originally posted by DeathEdge:

  pai seh.. cock eye -.- but * is X(times) right?

  yah.. dun want to confuse by using x which could mean i m using algebra to solve it. .and i think p sch maths cant use algbra still
• newcomer

  5 Apr 06, 23:36

  Originally posted by Ecxentrique:

  yah.. dun want to confuse by using x which could mean i m using algebra to solve it. .and i think p sch maths cant use algbra still

  They do!
• Ecxentrique

  5 Apr 06, 23:37

  Originally posted by newcomer:

  Why is 246 = 2 units of the expense ratio? Why not salary ratio?

  cos the salary ratio is reduced from 20:15 to become 4:3. (reduce by 5 times)
  
  so the more precise representation of the unit to the real money has to be related to the expanded ratio units and not the reduced one.. else will underestimate
• babymac13

  5 Apr 06, 23:38

  should be able to use simultaneous equation.
  
  Example
  Mr Koh: 4x = 246 + 18y
  
  let me know if you can solve.
  
  
• Xcert

  5 Apr 06, 23:39

  Originally posted by Ecxentrique:

  cos the salary ratio is reduced from 20:15 to become 4:3. (reduce by 5 times)
  
  so the more precise representation of the unit to the real money has to be related to the expanded ratio units and not the reduced one.. else will underestimate

  beri cheem explanation...anyway..Ecxentrique's answer correct or not?
• newcomer

  5 Apr 06, 23:40

  Originally posted by babymac13:

  should be able to use simultaneous equation.
  
  Example
  Mr Koh: 4x = 246 + 18y
  
  let me know if you can solve.
  
  

  What is x and y?
  Also, you can't solve an equation with 2 unknown unless you have another equation.
• DeathEdge

  5 Apr 06, 23:40

  Originally posted by Xcert:

  beri cheem explanation...anyway..Ecxentrique's answer correct or not?

  not correct i chop =x
• stem_-_daimyou_asobi_hen

  5 Apr 06, 23:41

  Originally posted by newcomer:

  Mr Koh's salary to that of his wife is in the ratio 4:3. Each of them saves $246 and spends the rest of their money. If Mr Koh's expenditure to that of his wife is in the ratio 18:13, find their total salaries.
  
  Any help would be much appreciated.
  
  P.S: Kind of embarrassed to not able to solve this qns for my little cousin.

  let mr koh salary be "x".
  his wife salary would be "3/4 x"
  
  $$ Mr koh spend is : x - 246
  $$ his wife spend is : 3/4x - 246
  
  "If Mr Koh's expenditure to that of his wife is in the ratio 18:13"
  hence,
  13 ( x -246 ) = 18 ( 3/4x - 246 )
  13x - 3198 = 13.5x - 4428
  0.5x = 1230
  x = 2460
  
  their combined salary is : x + 3/4x
  =7/4 x
  =7/4 ( 2460 )
  =$4305 !
  
  hope i'm right... well .. if it's a primary school question & there's no algebra.. guess u have to use table instead. (sorrie can't realli draw here.)