Math Is Fun Forum

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,422

Ration, Proportions, Work, Manpower

RPWM # 1

A can complete a piece of work in 4 days. B takes double the time taken by A. C takes double that of B, and D takes double that of C to complete the same task. They are paired in groups of two each. One pair takes two-thirds the time needed by the second pair to complete the work. How are the four paired?

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It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,422

Re: Ration, Proportions, Work, Manpower

RPWM # 2

A, B and C went to buy things from a wholesale market. They had a combined sum of $ 900. A spent 80%, B spent 70% and C spent 75% of their respective amounts. Now the ratio of amounts left with them is 4 : 9 : 10. Find the ratio of amounts they had in the beginning.

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It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

ashwil

Member

Registered: 2006-02-27

Posts: 121

Re: Ration, Proportions, Work, Manpower

#2

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,422

Re: Ration, Proportions, Work, Manpower

Excellent, Ashwil!

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It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,422

Re: Ration, Proportions, Work, Manpower

RPWM # 3

Three vessels contain mixtures of milk and water in the ratio 3:1, 4:1, and 5:1. The contents of the three vessels are mixed in the ratio x:y:1. If the resulting mixture contains milk and water in the ratio 7:1, find y in terms of x.

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It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

All_Is_Number

Member

Registered: 2006-07-10

Posts: 258

Re: Ration, Proportions, Work, Manpower

Last edited by All_Is_Number (2006-07-12 09:10:13)

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You can shear a sheep many times but skin him only once.

All_Is_Number

Member

Registered: 2006-07-10

Posts: 258

Re: Ration, Proportions, Work, Manpower

RPWM # 3

Three vessels contain mixtures of milk and water in the ratio 3:1, 4:1, and 5:1. The contents of the three vessels are mixed in the ratio x:y:1. If the resulting mixture contains milk and water in the ratio 7:1, find y in terms of x.

I'm not sure there is a valid solution to this problem. If 3:1 implies 3 parts milk to one part water, and 4:1 implies 4 parts milk to one part water, etc; there is no way to produce a solution of seven parts milk to one part water with the three solutions available. They will all have too much water. On the other hand, if 3:1 means three parts water to one part milk, etc; all possible solutions will have too much milk. One of the initial solutions must have a ratio higher than 7:1 in order to end up with a solution of 7:1. As the problem currently stands, I believe there are no real solutions.

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You can shear a sheep many times but skin him only once.

MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,713

Re: Ration, Proportions, Work, Manpower

I think that's right, AllIs.

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"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

tan

Member

Registered: 2010-02-17

Posts: 1

Re: Ration, Proportions, Work, Manpower

A & C , B&d

G-man

Member

Registered: 2011-02-28

Posts: 16

Re: Ration, Proportions, Work, Manpower

#3 isn't a valid problem because the ratio of the final mixture Should be between 3:1 & 5:1.
Still I calculated this.

Last edited by G-man (2011-02-28 20:13:36)

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Maths!......