Quant Quiz - A question a day

[kapildev]

Hi all,

This is towards my effort to get some questions solved in multiple ways. mostly am featuring borrowed questions. i know one solution to the question which i will post after 24 hours. in that time all can give their solutions and answers.

i will donate points (if i can accumulate that many) to the correct answers and the best answers. i decide what is correct . i may be wrong, and if you prove me wrong than i will donate more.
If you want questions to feature in my quiz, please pm that to me (with detailed solutions plz).

Kapil's Quiz Question 1

1. There are 100 friends and each has a purse containing 100 gold coins. One of the friends is a cheat and has a purse of 100 silver coins, that have been polished with gold so that one cannot make out the difference between the gold and silver coins visibly. You know that a gold coin weights 100 grams and a silver coin weights 99 grams.

Using a standard digital weighing scale, how many minimum weighs would you have to necessarily perform to find the purse containing silver coins ? You also have a pen, an extra gold coin weighing 100 grams and an extra silver coin weighing 99 grams.

1. 99 2. 33 3. 50 4. None of these

Please post solutions within 24 hours.

Kapil

[Nirav]

Answer is none of these
all we need is one weighing

take one coin from purse#1 (of frnd #1)
2 coins from purse #2 ...

n coins from purse #n...

100 coins fro m purse no 100

total expected weight = 1+2+3...+100 = 5050

if the kth purse has lighter coins the total weight will be less by "k" grams

so lo and behold we get the answer

regds

nirav

[Nirav]

Originally Posted by kapildev

Hi all,

i will donate points (if i can accumulate that many) to the correct answers and the best answers. i decide what is correct . i may be wrong, and if you prove me wrong than i will donate more.

sirji thoda points mere jawaab ko do

Originally Posted by kapildev

You also have a pen, an extra gold coin weighing 100 grams and an extra silver coin weighing 99 grams.

arre do u need these things ??? or are they to phasao ppl

Originally Posted by kapildev

1. 99 2. 33 3. 50 4. None of these

these options look as if for the weighing balance (vajan ka kata type problems .. not a digital scale...

also abhi koi ponts dedo re mujhe

nirav

[PRGKT]

Why only one question a day? Increase the number yaar. Make it 5 at least.

[MavericK]

why whats wrong with the "Quant Teasers" thread ?

[TheAkshaT]

Yeah let's Keep...

"One Thread to Rule them all" ...

It'll be easy for guys looking for archives of the quant questions on the forum...

-Akshat

[kapildev]

Great reply nirav,
Absolutely correct. Will donate points when i cross a 1000.
Yes, some of the information was not required to solve the problem.

Will post 5 if i have that many good ones. Pleez. send your contributions to me, and i will try and screen them.

Anyway,
Here are three moderate ones (I hope). There must surely be a lot of ways to answer these.

Kapil's Quiz Corner : Day 2

1. In how many numbers less than a lakh and more than a thousand does the digit 5 get repeated more than once ?

2. How many numbers from 1 to 10000 are such that number of digits that are even is equal to number of digits that are odd ?

3. How many numbers from 1 to 10000 are such that the sum of the digits in the even place is equal to the sum of the digits in the odd place ?

My answers tomorrow.

[MavericK]

Hey, Before you go on with your Quiz, the general rules apply.
1: Quizmaster specify deadline and the time when u r gonna post the answer
2: Junta dont post answers here. Instead send them as e-mail or PM to the user who has started the Qn.
This way shd help others to work out their own solutions.
And if the Quizmaster is patient enough, then he can post all the "correct solns" and hence choose the best and effective way of answering the Qn.
hth!

[kapildev]

Thanks Maverick, suggestion noted.

Quiz Day 2 expiry time : Thursday 27 May - 5.00 p.m. by my watch

I will post all correct solutions and also wrong ones so that junta can know where we make mistakes.

PM ur answers before 5.00 tmrw. My answers on the forum by 6.00.

Kapil

[RahulSharma]

Here's mine for 28th.

How many n are there such that n^2 + 5*n + 8 is a perfect square?

(a) 2 (b) 0 (c) 1 (d) Infinitely many