Logic Quiz

[MustafaQuraishi]

Re: Logic Quiz

@bitter

sorry misread your question as 10 coins of 1 g each hence the total weight came to be 55..

so he will pick 55 coins total - so the weight should 550 g

now if the goldsmith no 5 is the thief - then then the shortfall should be 5g hence the total weight would be 545.

CORRECT - Electra aap ka hoa

[Eastern_Dresses]

Re: Logic Quiz

^lol

[MustafaQuraishi]

Re: Logic Quiz

@Eastern_Dresses

^lol

did you check my answer to your question ?

[mahool]

Re: Logic Quiz

@Eastern_Dresses

In front of you are 3 chests:
Chest A has been labelled with “100 gold coins”,
Chest B has been labelled with “50 gold and 50 silver coins”,
Chest C has been labelled with “100 silver coins”.

You are told that all of the labels are incorrectly placed, as they describe the contents of another chest. To help you determine which is the chest which contains “100 gold coins”, you are allowed to randomly pick a coin from any chest,

Which chest should you pick a coin from?

If boxes are incorrectly labeled, then 100 gold coins should be in Chest C… :hehe:

[mahool]

Re: Logic Quiz

Bob or Andrew.. they either wearing red or blue...

[Eastern_Dresses]

Re: Logic Quiz

@mahool

If boxes are incorrectly labeled, then 100 gold coins should be in Chest C…

Not necessarily. 100 gold coins can either be in Chest B or Chest C. Please read the solution.

@MustafaQuraishi

did you check my answer to your question ?

Yes I did, the logic is correct but it didn’t need that detailed explanation Saying both lied would have been enough explanation.

Are you going to post the next quiz now?

[SID_NY]

Re: Logic Quiz

@MustafaQuraishi

how wouldn’t he show up ? the “10th” day has nothing to do with the question @bitter has already solved it. Think about how would you index an object. Think about very layman indexing solution and for hat you don’t need days. all you need is your objects which are the coins in the bag

Nah I dont get it.. not at all.. and yes u can totally mark me as dumb :bummer:

[mahool]

Re: Logic Quiz

@Eastern_Dresses

Not necessarily. 100 gold coins can either be in Chest B or Chest C. Please read the solution.

^ Ok.

[MustafaQuraishi]

Re: Logic Quiz

@SID_NY

Nah I dont get it.. not at all.. and yes u can totally mark me as dumb :bummer:

@mahool did that on my behalf i.e., marking you as a dumb person.

Okay so here is the explanation. First thing is that we need to figure out how to find that culprit. Given that we can use the scale only once and can take only one reading, we need to come up with a technique that no matter how we take the reading, we somehow know “which bag has the lighter coins”.

Now once you know that you have to find the “which” bag. you should starting thinking about the objects i.e., how can you index those bags in a way that each bag represent its weight ?

Now lets bring some math in and take some help from magical # 9. The beauty of this number is that the number of times you add it, it will give you 2 things

1. Sum of the number of times you have added
2. Difference from the next “decimal” place

So lets add 2 times.

9 + 9 = 18 (it is 2 places away from closest decimal i.e., 20)

lets add 9 6 times
9 + 9 + 9 + 9 + 9 + 9 = 54 (its 6 places away from next decimal point i.e., 60)

So using 9, you can index those bags. i.e., label all those bags as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. For the sake of explanation lets say i have only 3 bags. so label would be 1, 2, 3

Now, pick number of coins which correspond to the bag number. (assume bag 2 has 9g coins)

So from

bag 1, I will pick 1 coin = 1 x 10 = 10
bag 2, I will pick 2 coins = 2 x 9 = 18
bag 3, I will pick 3 coin = 3 x 10 = 30

sum it up = 58

But total should have been 60 ? which means it lacks 2 grams which means that the coins which are picked from bag 2 are the ones which has bad coins.

Now you can apply this same logic to all bags.

p.s: why did i chose number 9 ? because the coins weigh 9 and that was the biggest hint. had those weight 8 or something else things would have been difficult.

[MustafaQuraishi]

Re: Logic Quiz

**Alright guys Next one

**Before i go on to one of my favourite and possible the toughest one, here is another easy one.

You are given 8 balls and you have a balance scale. You can use this scale as many time as you want. All balls are of same weight except 1 (which weighs lighter). Now tell me minimum number of times you need to use the scale to figure out which ball is this ?

p.s:
for people who don’t know what a balance scale is https://upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Balanced_scale_of_Justice.svg/1280px-Balanced_scale_of_Justice.svg.png

[MustafaQuraishi]

Re: Logic Quiz

@Eastern_Dresses

Not necessarily. 100 gold coins can either be in Chest B or Chest C. Please read the solution.

Yes I did, the logic is correct but it didn’t need that detailed explanation Saying both lied would have been enough explanation.

Are you going to post the next quiz now?

Already did … http://www.paklinks.com/gs/general/657960-logic-quiz-post10321865.html#post10321865

[mahool]

Re: Logic Quiz

@MustafaQuraishi My okay was response to Eastern Dresses post on reading solution of first quiz.

[MustafaQuraishi]

Re: Logic Quiz

@mahool

@MustafaQuraishi My okay was response to Eastern Dresses post on reading solution of first quiz.

no worries, I can mark @SID_NY a dumb one … not a big deal

[SID_NY]

Re: Logic Quiz

@MustafaQuraishi

**Alright guys Next one

**Before i go on to one of my favourite and possible the toughest one, here is another easy one.

You are given 8 balls and you have a balance scale. You can use this scale as many time as you want. All balls are of same weight except 1 (which weighs lighter). Now tell me minimum number of times you need to use the scale to figure out which ball is this ?

p.s:
for people who don’t know what a balance scale is https://upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Balanced_scale_of_Justice.svg/1280px-Balanced_scale_of_Justice.svg.png

If its another mathematical quiz, i aint diving in..

[MustafaQuraishi]

Re: Logic Quiz

@SID_NY

If its another mathematical quiz, i aint diving in..

its more of computer science than math. biggest hint

[mahool]

Re: Logic Quiz

@MustafaQuraishi

**Alright guys Next one

**Before i go on to one of my favourite and possible the toughest one, here is another easy one.

You are given 8 balls and you have a balance scale. You can use this scale as many time as you want. All balls are of same weight except 1 (which weighs lighter). Now tell me minimum number of times you need to use the scale to figure out which ball is this ?

p.s:
for people who don’t know what a balance scale is https://upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Balanced_scale_of_Justice.svg/1280px-Balanced_scale_of_Justice.svg.png

8 balls…

4 on left and 4 on right… lighter side will go up… 1 time

take two balls from lighter side and removed the ball from other side and place two balls in it… - 2 nd time..

Repeat same method… 3 rd time.

You can use scale three time … :cobra:

P.s. solved problem.. feeling bigger balls… :devil:

[SID_NY]

Re: Logic Quiz

@MustafaQuraishi

**Alright guys Next one

**Before i go on to one of my favourite and possible the toughest one, here is another easy one.

You are given 8 balls and you have a balance scale. You can use this scale as many time as you want. All balls are of same weight except 1 (which weighs lighter). Now tell me minimum number of times you need to use the scale to figure out which ball is this ?

p.s:
for people who don’t know what a balance scale is https://upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Balanced_scale_of_Justice.svg/1280px-Balanced_scale_of_Justice.svg.png

3 times.

And tried it on basic logic not on any computer etc terms.

You know i got a degree in CS from Axact

[MustafaQuraishi]

Re: Logic Quiz

@mahool

8 balls…

4 on left and 4 on right… lighter side will go up… 1 time

take two balls from lighter side and removed the ball from other side and place two balls in it… - 2 nd time..

Repeat same method… 3 rd time.

You can use scale three time … :cobra:

P.s. solved problem.. feeling bigger balls…

@SID_NY

3 times.

And tried it on basic logic not on any computer etc terms.

You know i got a degree in CS from Axact

I am not satisfied your answer. you guys used binary search here but binary search isn’t efficient here. could you make it more efficient ?

[mahool]

Re: Logic Quiz

@MustafaQuraishi

I am not satisfied your answer. you guys used binary search here but binary search isn’t efficient here. could you make it more efficient ?

In that case, scale will at most used by 7 and at least by 1. :cobra:

What will be Big(o) notation of sort? 7?

[SID_NY]

Re: Logic Quiz

@MustafaQuraishi

I am not satisfied your answer. you guys used binary search here but binary search isn't efficient here. could you make it more efficient ?

Not satisfied with the answer or with the explaination? Answer will either be right or wrong