Question about Mathsoft StudyWorks! Mathematics Deluxe 5.0 (11513) for PC

They are 4 years old and the mother is 32. This is a system of two equations. The first equation is 28 + x (their mother is 28 years older than they are). The second equation is 8x (she is 4 times as old as their sum) their sum is 2x (x being the twins age) time 4 which is 8x. Set these two equal to each other and you get 28 + x = 8x, bring the x to the other side by subtracting and x on both sides and you end up with 28=7x , now divide off the 7 and get x=4. Verify your work and take 4 + 28 and you get 32. Now take 4*2 (sum of their ages ) and multiply it by 4 and you get 32.

Posted on Jun 26, 2009

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Posted on Jan 02, 2017

Let Adjoa's age be x and Kwame's y.

- Adjoa is 3 years older than Kwame: x=y+3
- Seven years ago sum of their ages was 13: (x-7)+(y-7)=13
- Now you substitute first equation into second equation: (y+3-7)+(y-7)=13
- 2y-4-7=13
- 2y=24
- y=24/2=12 years
- x=y+3=12+3=15 years
- sum of their present ages is x+y=12+15=27 years

Sep 27, 2011 | Office Equipment & Supplies

Let m be Marian's age, d Diana's age and c Carlos age.

I hope I helped :)

- sum of ages is 17: m+d+c=17
- two years from now Marian will be twice as old as Diana: m+2=2*(d+2) so m+2=2d+4 so 2d=m-2 or d=(m-2)/2=m/2-1
- Carlos will be half as old as Marian 4 years from now: c+4=1/2(m+4) or c+4=m/2+2 or c=m/2-2
- now: m+d+c=m+m/2-1+m/2-2=17
- 2m=17+3=20
- m=20/2=10 years
- d=m/2-1=5-1=4 years
- c=m/2-2=5-2=3 years

I hope I helped :)

Sep 18, 2011 | Office Equipment & Supplies

let c = cory's age now
let s = her sisters age now

cory's age now = sisters age + 6 years

=> c = s + 6

4 years ago, cory was 4 years younger ( i.e. c-4) and her sister was 4 years younger (s- 4)

4 years ago cory was 4 times older than her sister

=> c - 4 = 4*(s-4)

We can simplify this to c = 4s - 16 +4 c = 4s - 12

We can then use simultaneous equations to solve the two equations

(i) c = s + 6 (ii) c = 4s - 12

If we multiply both sides of equation (i) by 4 we get (iii) 4c = 4s + 24

We can then subtract equation (ii) from equation (iii) to eliminate the '4s' term => ( 4c = 4s + 24 ) - (c = 4s - 12) => 4c - c = 4s +24 - 4s +12 => 3c = 4s - 4s +36 => 3c = 36 => c = 36/3 => c = 12 => Cory's age now = 12

__For clarity:__
Her sister's age now is of course 6
4 years ago Cory would of been 8 and her sister would of been 2

I hope this helps and good luck! If you have more questions - ask away!

Please take the time to rate this answer

Many Thanks Don.

cory's age now = sisters age + 6 years

=> c = s + 6

4 years ago, cory was 4 years younger ( i.e. c-4) and her sister was 4 years younger (s- 4)

4 years ago cory was 4 times older than her sister

=> c - 4 = 4*(s-4)

We can simplify this to c = 4s - 16 +4 c = 4s - 12

We can then use simultaneous equations to solve the two equations

(i) c = s + 6 (ii) c = 4s - 12

If we multiply both sides of equation (i) by 4 we get (iii) 4c = 4s + 24

We can then subtract equation (ii) from equation (iii) to eliminate the '4s' term => ( 4c = 4s + 24 ) - (c = 4s - 12) => 4c - c = 4s +24 - 4s +12 => 3c = 4s - 4s +36 => 3c = 36 => c = 36/3 => c = 12 => Cory's age now = 12

I hope this helps and good luck! If you have more questions - ask away!

Please take the time to rate this answer

Many Thanks Don.

Sep 13, 2011 | Sunburst My Mathematical Life Single...

daughter = x

mother = x+28

Equation = x+28=3x

Solve:

x+28=3x

-x -x

28 = 2x

/2 /2

x=14

Answer:

Daughter = 14

Mother = 42

mother = x+28

Equation = x+28=3x

Solve:

x+28=3x

-x -x

28 = 2x

/2 /2

x=14

Answer:

Daughter = 14

Mother = 42

Mar 04, 2011 | Computers & Internet

The average is 20, it means the total is 60. The sum of ratio is 15 (3+5+7)

Therefore the age of a girl is calculated by multiplying the respective ration with total and dividing by sum of ratio

Age of Eldest girl = 7 x 60 /15 = 28

Hope it helps! Good Luck!

CreativeTECH

Therefore the age of a girl is calculated by multiplying the respective ration with total and dividing by sum of ratio

Age of Eldest girl = 7 x 60 /15 = 28

Hope it helps! Good Luck!

CreativeTECH

Feb 15, 2011 | Computers & Internet

Jamie = x

Luiz = x+4

Ramon = x+7

3x+11=29

3x=18

x=6

Jamie = 6 , Luiz = 6+4 = 10 , Ramon = 6+3 = 13

Luiz = x+4

Ramon = x+7

3x+11=29

3x=18

x=6

Jamie = 6 , Luiz = 6+4 = 10 , Ramon = 6+3 = 13

Oct 13, 2010 | MathRescue Word Problems Of Algebra Lite

X= (1/2)M + 3
2 + X + 20 = M - 6

The father statement is not needed.

Two variables, with two equations. Solve for X.

The father statement is not needed.

Two variables, with two equations. Solve for X.

Sep 29, 2010 | Cameras

Three unknowns with three equasions:

cindy is 5 years older than alex. write it as c = a + 5

cindy is 7 years older than peter. write it as c = p + 7

The sum of their ages is 21. write it as c + a + p = 21

first solve for peters age in terms of alex's age.

c = p + 7 or

(a + 5) = p + 7 or

p = (a + 5) - 7 or

p = a - 2

substitute in and solve the equasion:

(a + 5) + a + (a - 2) = 21 or

3a + 3 = 21 or

3a = 24 or

a = 8

c = a + 5 or

c = 8 + 5 = 13

c = p + 7 or

p = c - 7 or

p = 13 - 7 = 6

cindy is 13, alex is 8 and peter is 6

This is called simultaneous equasions and will always work if you have the same number of unknowns as you have equasions (or relationships).

cindy is 5 years older than alex. write it as c = a + 5

cindy is 7 years older than peter. write it as c = p + 7

The sum of their ages is 21. write it as c + a + p = 21

first solve for peters age in terms of alex's age.

c = p + 7 or

(a + 5) = p + 7 or

p = (a + 5) - 7 or

p = a - 2

substitute in and solve the equasion:

(a + 5) + a + (a - 2) = 21 or

3a + 3 = 21 or

3a = 24 or

a = 8

c = a + 5 or

c = 8 + 5 = 13

c = p + 7 or

p = c - 7 or

p = 13 - 7 = 6

cindy is 13, alex is 8 and peter is 6

This is called simultaneous equasions and will always work if you have the same number of unknowns as you have equasions (or relationships).

Sep 20, 2009 | Puzzle Toys

Nov 08, 2011 | Mathsoft StudyWorks! Mathematics Deluxe...

Jul 26, 2010 | Mathsoft StudyWorks! Mathematics Deluxe...

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