Logical reasoning question - I

[Qwertyuiop[]]

Hi, I have this logical reasoning question. How do you go about these logical reasoning questions? It's the first I've come across these and I would like to know how do you guys tackle them.




Discussing their personal finances, four friends (Dilya, Gulzoda, Laziza e Tenkokuheya) state that:

- Dilya has less money than Laziza
- Gulzoda has less money than Laziza
- Laziza has more money than Tenkokuheya
- Gulzoda has more money than Dilya

Then, which of the following statements is NOT NECESSARILY correct?

(a) Gulzoda is not the poorest
(b) Tenkokuheya has less money than Laziza
(c) the alphabetical order of the names is not the same as the (increasing order) of the money owned
(d) the richest among the friends is Laziza
(e) Dilya is the poorest among the friends

 

[blamocur]

Start with a simpler example:

• If A has less money than B, and B has less money than C then who has more money: A or C?
• Is B the poorest?

 

[Dr.Peterson]

Hi, I have this logical reasoning question. How do you go about these logical reasoning questions? It's the first I've come across these and I would like to know how do you guys tackle them.

Discussing their personal finances, four friends (Dilya, Gulzoda, Laziza e Tenkokuheya) state that:

- Dilya has less money than Laziza
- Gulzoda has less money than Laziza
- Laziza has more money than Tenkokuheya
- Gulzoda has more money than Dilya

Then, which of the following statements is NOT NECESSARILY correct?

(a) Gulzoda is not the poorest
(b) Tenkokuheya has less money than Laziza
(c) the alphabetical order of the names is not the same as the (increasing order) of the money owned
(d) the richest among the friends is Laziza
(e) Dilya is the poorest among the friends

What I tend to do for these is to imagine putting them on a number line, making "puzzle pieces" I can fit together. For example, the first statement would be represented by "D----L", meaning that D will be placed to the left of L. Then I use all the pieces to see what is known about the arrangement as a whole. We'll end up with at least one person who could go in more than one place.

Then I see which questions have definite answers.

Let us know what you find.

 

[JeffM]

Use symbols and then think about what the symbols mean

First, D < L.
Second, G < L.
Third, T < L.
Fourth, D < G.

What is absolutely certain is

Fifth, D < L.

If G is the poorest, then G < D. Contradicts 4. So a is necessarily correct.

Keep going.

 

[Qwertyuiop[]]

Hi, thank you for replying JeffM, Dr.Peterson and blamocur , that was very helpful.
So as you suggested I used symbols like this:
L > D
L > G
L > T
G > D
and then looked at each question. e) is the one that is NOT NECESSARILY correct as the question says.

Option a) Gulzoda is not the poorest : This one is obviously correct because of the relationship G > D . G has more money then D so can not be the poorest.

Option b) Tenkokuheya has less money than Laziza : Correct because L > T which is the same as T < L so T has less money then L.

Option c) the alphabetical order of the names is not the same as the (increasing order) of the money owned : The alphabetical order of their names is D G L T . T is not the wealthiest and D is not the poorest so this option also seems right.

Option d) the richest among the friends is Laziza : The statement is correct from the above relationships. L has more money then D G and T.

Option e) Dilya is the poorest among the friends : This one is not necessarily correct because we don't know how D and T compare and we can not establish it from the above relationships. We know that D < L , D < G but we don't for sure if D < T so it's not certain if Dilya is the poorest.

So this is my reasoning and option e) is the answer. Would anyone like to add something to this ? Thanks

 

[blamocur]

Hi, thank you for replying JeffM, Dr.Peterson and blamocur , that was very helpful.
So as you suggested I used symbols like this:
L > D
L > G
L > T
G > D
and then looked at each question. e) is the one that is NOT NECESSARILY correct as the question says.

Option a) Gulzoda is not the poorest : This one is obviously correct because of the relationship G > D . G has more money then D so can not be the poorest.

Option b) Tenkokuheya has less money than Laziza : Correct because L > T which is the same as T < L so T has less money then L.

Option c) the alphabetical order of the names is not the same as the (increasing order) of the money owned : The alphabetical order of their names is D G L T . T is not the wealthiest and D is not the poorest so this option also seems right.

Option d) the richest among the friends is Laziza : The statement is correct from the above relationships. L has more money then D G and T.

Option e) Dilya is the poorest among the friends : This one is not necessarily correct because we don't know how D and T compare and we can not establish it from the above relationships. We know that D < L , D < G but we don't for sure if D < T so it's not certain if Dilya is the poorest.

So this is my reasoning and option e) is the answer. Would anyone like to add something to this ? Thanks

Looks good to me.

 

[sakshijn]

According to question
D<L
G<L
T<L
D<G
OPTION e:- Dilya is the poorest among the friends: This one is not necessarily correct because we don't know how D and T will arrange. We know that D < L , D < G but we don't know about D < T or T< D so it's not confirmed if Dilya is the poorest.