Official Quant thread for CAT 2013

MBA CAT 2024
15503
@ravi.theja said:
What is the maximum number that one cannot obtain as a linear combination of 9 and 20?a) 171b) 151c) 141d) 155 e) 145
151 ?
15504
@ravi.theja said:
What is the maximum number that one cannot obtain as a linear combination of 9 and 20?a) 171b) 151c) 141d) 155 e) 145
b. 151

15505
@gs4890 said:
151 ?
approach ??
15506
The sum of digits of a natural number (10^n €“ 1) is 4707, where n is a natural number. The value of n is ??
(1) 477 (2) 523 (3) 532 (4) 704

P.S. Don't have the OA..
15507
@Shray14 said:
The sum of digits of a natural number (10^n €“ 1) is 4707, where n is a natural number. The value of n is ??(1) 477 (2) 523 (3) 532 (4) 704 P.S. Don't have the OA..
523 😃 10^2- 1 = 99 ...10^3 - 1 = 999...so the resulting number ll hav only 9's...

9x = 4707 ==> x= 523...so n = 523
15508
@Shray14
2: 523
15509
@Shray14 said:
The sum of digits of a natural number (10^n €“ 1) is 4707, where n is a natural number. The value of n is ??(1) 477 (2) 523 (3) 532 (4) 704 P.S. Don't have the OA..
523?
9*x=4707
x = 523
15510
@Shray14

Given, N= 10^n -1 is a Natural Number whose sum is 4707..

Caselet study reveal few points: At n=1, N=9..number of 9=1, Sum of such number 1*9

At n=2, N=99..number of 9=2, Sum of such number 2*9

At n=3, N=999..number of 9=3, Sum of such number 3*9

Thus, Simply putting, 4707 is the sum of x*9... Here, x=523..which is the number of 9 used..

Thus, n will be 523..
15511
@raopradeep said:
find possible value of the sum of the squares of roots of the eqnx^2 - (a-3)x + 5-a=0a) -3b) -8c) -7d) -9
OA is A
15512
@raopradeep said:
find possible value of the sum of the squares of roots of the eqnx^2 - (a-3)x + 5-a=0a) -3b) -8c) -7d) -9
OA is A
15513

the number of no-zero digits in (101010101)^2

options:5,8,9,18
15514
@ravi.theja said:
-3.let x and y be the roots ==> x^2 + y^2 = (x+y)^2 - 2*x*y = (a-3)^2 -2 *(5-a)= a^2 - 6a+9 -10+2a = a^2 -4a -1 = (a-2)^2 -5here (a-2)^2 is always +ve..so minimum value is -5 ..so only -3 is greater than -5 .... so its -3
can "a" takes complex numbers then only -3 can come i think plz rectify if iam wrong
15515
@anitito123 said:
the number of no-zero digits in (101010101)^2options:5,8,9,18
5??
15516
@raopradeep said:
can "a" takes complex numbers then only -3 can come i think plz rectify if iam wrong
a = root 2 + 2 ; ...u ll get -3..its not complex na, a is not a integer here..dats all
15517
@anitito123 said:
the number of no-zero digits in (101010101)^2options:5,8,9,18
9?
15518
@gs4890 said:
151 ?
kaise hoga yeh??
15519
@ravi.theja yes i typed wrong a is not integer
15520
@anitito123
c: 9?
15521
@stellarPG @ravi.theja @mailtoankit @anantn OA is 9.Approach Please.

15522
solve:

2(root2+root6)/(3*root(2+root3))

Options: 4/3, 1, 16/9, 2/3