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[MathIzzzFun]

sylpha:

MathIzzzFun:

[quote=\"sylpha\"]Rick sold a total of 90 chickens and ducks. He earned a total of $4 in every duck he sold and lost $2 on every chicken he sold. On the whole, he earned a total of $222. How many ducks and chickens did he sell?


Hi

number of chickens = [(90x4)-222]/6 = 23
number of ducks = 90 - 23 = 67

cheers.

Hi there
Btw, how would this be illustrated in the model method? I sort of understand the logic I cant graphically \"draw\" it.

some examples here -
http://www.flickr.com/photos/62167097@N02/6963704884/in/set-72157629901522689

http://www.flickr.com/photos/62167097@N02/6808896113/in/set-72157629901522689

http://www.flickr.com/photos/62167097@N02/7634466300/in/set-72157629901522689

http://www.flickr.com/photos/62167097@N02/7319052572/in/photostream

cheers.

Many thanks for the awsome solutions! :salute:

My logic: I managed to piece together the \"logic\" using your graph. Basically, if I had to throw out a duck (90 ducks, max value $360) for 1 darn chicken, it would mean I would lose $6. so thats why $138/$6 => 23 chickens![/quote]yep, that's right.

cheers.

[kwcllf]

Hi please help



When k patners l, they take 8 days to paint a house. When b patners h, they take 6 days to paint the house. When h patners m, they take 12 days to paint a house. How many days do k and m take to paint the house together?

Thanks

[kwcllf]

Sorry, first sentence should be when k patners b, they take 8 days to paint the house.

[MathIzzzFun]

kwcllf:

Hi please help



When k patners b, they take 8 days to paint a house. When b patners h, they take 6 days to paint the house. When h patners m, they take 12 days to paint a house. How many days do k and m take to paint the house together?

Thanks

Total work required to paint a house --> 120 units
K+B --> 120 units/8 days = 15 units/day
B+H --> 120 units/ 6 days --> 20 units/day
H+M --> 120 units/12 days --> 10 units/day
K+B+B+H+H+M --> 45 units/day
K+M --> 5 units/day (B+H --> 20 units/day)
120 units --> 120/5 = 24 days

K+M will take 24 days to paint the house.

cheers.

[kwcllf]

MathIzzzFun:

kwcllf:

Hi please help



When k patners b, they take 8 days to paint a house. When b patners h, they take 6 days to paint the house. When h patners m, they take 12 days to paint a house. How many days do k and m take to paint the house together?

Thanks

Total work required to paint a house --> 120 units
K+B --> 120 units/8 days = 15 units/day
B+H --> 120 units/ 6 days --> 20 units/day
H+M --> 120 units/12 days --> 10 units/day
K+B+B+H+H+M --> 45 units/day
K+M --> 5 units/day (B+H --> 20 units/day)
120 units --> 120/5 = 24 days

K+M will take 24 days to paint the house.

cheers.

Hi,

Wonder if you could enlighten me if I solve the question in the following manner:

K+B= 8 ------ (1)
B+H = 6 -------(2)
H+M = 12 -----(3)

(1) minus (2) ----> K-H = 2 -----> H = K-2, substitute into Equation (3)

H+M =12
(K-2)+M = 12
K+M = 14

The answer is different from your solution. Is there something wrong with my solution? Thanks!

[MathIzzzFun]

kwcllf:

MathIzzzFun:

[quote=\"kwcllf\"]Hi please help



When k patners b, they take 8 days to paint a house. When b patners h, they take 6 days to paint the house. When h patners m, they take 12 days to paint a house. How many days do k and m take to paint the house together?

Thanks

Total work required to paint a house --> 120 units
K+B --> 120 units/8 days = 15 units/day
B+H --> 120 units/ 6 days --> 20 units/day
H+M --> 120 units/12 days --> 10 units/day
K+B+B+H+H+M --> 45 units/day
K+M --> 5 units/day (B+H --> 20 units/day)
120 units --> 120/5 = 24 days

K+M will take 24 days to paint the house.

cheers.

Hi,

Wonder if you could enlighten me if I solve the question in the following manner:

K+B= 8 ------ (1)
B+H = 6 -------(2)
H+M = 12 -----(3)

(1) minus (2) ----> K-H = 2 -----> H = K-2, substitute into Equation (3)

H+M =12
(K-2)+M = 12
K+M = 14

The answer is different from your solution. Is there something wrong with my solution? Thanks![/quote]hi
this is a work rate question... so, have to work on per unit time basis.
eg we use K+B+H+M --> 20 -- this means that all four working together will take 20 days to complete the job, which is incorrect.

If all are working together, we expect that time taken will be less...therefore, need to work on per unit time basis eg if A complete the work in X days, and B completes the work in Y days, then X will complete 1/X of the work in 1 day, and B complete 1/Y of the work in 1 day and both A & B will complete (1/X + 1/Y) of the work in one day.

cheers.

[Herbie]

I hv one qn.


On a map, an area of 200 cm sq represents an actual area of 8km sq
A. Ifthe map has a scale of 1:k, find the value of k
B. If the distance between two points on the
map is 3cm, find the actual distance in km between two points.

Can show the steps pls? Tq

[MathIzzzFun]

http://i46.tinypic.com/s15mkw.png\">


cheers.

[Herbie]

MathIzzzFun:

deleted

Hi noted u hv deleted yr answer.

[MathIzzzFun]

MathIzzzFun:

http://i46.tinypic.com/s15mkw.png\">


reposted

cheers.