[user1285]

Originally Posted by dare2

which test are you talking about?? can i have the link of that?

Power Play I ( 30 August 200 Ultimate Quant Marathon Blog For IIM CAT

[hismajesty143]

Originally Posted by shivam_01

Moving on to next question >>>>>

On a number line, the first 20 natural numbers are selected and 10 of them are painted black and ten of them are painted white. Let a1, a2, a3, ....., a10 be painted black such that a1 < a2 < a3 ..... < a10 and let b1, b2, b3, ....., b10 be painted white such that b1 > b2 > b3 > ..... > b10. Then the value of |a1 - b1| + |a2 - b2| + |a3 - b3| + ..... + |a10 - b10|
is
odd
is even
lies between 20 and 30
lies between 10 and 20
cannot be determined

It has to be even.

Let two random series of a and b be written as follows:
Series of a: 1,3,4,7,8,11,17,19,20
Series of b: 18,16,15,13,12,9,6,5,2

Please note that the series of b is dependant on the values of the series a.
Here, if you find out the sum, you will get it +ve.
Now try changing the series, for every increase/decrease in the values of a, there MUST be a corresponding decrease/increase in the values of b.
HENCE, in all situations, the answer will be even

[mahi101987]

Let a1 = x, b1 = y, where x and y are positive.
an = x + bn-1, bn = y + bn-1 for even n > 1.
an = x + an-1, bn = y + an-1 for odd n > 1.


If x = 3/4 and y = 1/4, then which is the highest odd n for which (an)/(bn) > 1.05?
21
20
17
19
23

[dare2]

wrong post

[hismajesty143]

Originally Posted by shivam_01

Kya baat hain koi activity nahi yahan par masoom shivani kahan gaye ho .....

any ways new question from my side ..


The language CAT has only three letters C, A and T. In this language every combination of letters is a word except those in which A is followed by a T. How many four-letter words are there in CAT?
80 78 72 55 71

The correct answer is 55.
Good question though. Had a little twist to it.

Explanation

Total permutations possible, without any restriction : 3*3*3*3 = 81
Restriction is that if T is placed after A, it is not a word.
Hence, keeping AT fixed, the other two letters can be selected in 3*3=9 ways. This can be done in three positions.
Hence we get 9*3=27

However (and here's the interesting part), there is a word ATAT, which is counted twice. Two remove this double counting effect, we subtract 1 from 27.

Hence, our answer = 81-(27-1) = 91-26 = 55

[hismajesty143]

Taking from a QQAD:

Priyanka does daily work for a fixed time, and her efficiency would reduce by 10% on each subsequent day. However, when she took a break for a day her efficiency would come to normal the next day. Assume Priyanka worked for a long time, then after how many days of consecutive work does she needs to take a break to have the maximum output?

I want to do this some using Maxima Minima and I want to construct a function of the form y=f(x) where y is the efficiency and x is the number of the day with which the efficiency would collide.

Eq: if y=1, x=100
if y=2, x=90
if y=3, x=81, and so on.....

Can anyone form the function??

Note: I am not looking for the solution to the question. The question can be solved in a much easier way. What I am looking for is a tutorial on how to create functions, when such information is given using the above question as an example.

[Varun Khullar]

Originally Posted by HYgoldking

1) Two different positive numbers a and b differ from their reciprocals by 1. Find a+b
A) 1 B) √6 c) √5 D) 3 E) None of these.
A) 1

3) How many subsets of the set {1,2,3…,30} have the property that the sum of all elements is more than 232?
A) 2^30 B) 2^29 C) 2^29 -1 D) 2^29+1 E ) None of these

E ) None of these

4) Let the point P be (4,3). Choose a point Q on y=x line and another point R on the line y=0 such that sum of lengths PQ+QR+PR is minimum. Find this minimum length.
A) 5√2 B) 3+3√2 C) 5 D) 4 E) 10
c) 5

5) Let f be a function defined on odd natural numbers which return natural numbers such that f(n+2)=f(n)+n
and f(1)=0 . Then f(201)?
A) 10000 B)20000 C) 40000 D) 2500 E) None of these

A) 10000

7) The product of n numbers is n and their sum is 0. Then n is always divisible by
A) 3 B) 4 C) 5 D) 2 E) None of the foregoing

B) 4

answer to
1 is root 5 take positve numbers
3 is B 2^29
4 B 3+3root2
5 is none of these
7 is always divisble by 4

[raghav507]

Originally Posted by HYgoldking

4) Let the point P be (4,3). Choose a point Q on y=x line and another point R on the line y=0 such that sum of lengths PQ+QR+PR is minimum. Find this minimum length.
A) 5√2 B) 3+3√2 C) 5 D) 4 E) 10
c) 5

hi,
the minimum distance will yield if we have Q and R as the same point...as (0,0)
this makes the given figure as a right angled triangle with hypotenuse as 5 and hence the min distance is 5...

[HYgoldking]

Originally Posted by Varun Khullar

answer to
1 is root 5 take positve numbers
3 is B 2^29
4 B 3+3root2
5 is none of these
7 is always divisble by 4

Please explain the 3rd answer (3 is B 2^29)

Thanks

[dare2]

Originally Posted by raghav507

hi,
the minimum distance will yield if we have Q and R as the same point...as (0,0)
this makes the given figure as a right angled triangle with hypotenuse as 5 and hence the min distance is 5...

check ur solution again.
as per the conditions laid down by u, its not 5 but 10.

PQ=5
QR=0
PR=5
hence total distance as per your method is 10 not 5