Official Quant thread for CAT 2013

MBA CAT 2022
921
@krum 21 is the answer
922
@pussu01 said:
bhai iska answer kya hai ? mujhe to qn hi samajh me nahi aaya achhe se.
total number of people to be tested to hai hi nahi
par if what i am thinking is correct to answer none of these diya hai kya?
bhai fir bhi jo bhi logic hai post karo maybe someone else will figure it out
21
923
@techsurge said:

Another One from IIFT from my side

A tough one

A medical tests blood for certain diseaase from which approximately one person in a hundred suffers. People come in clinic in group of 50, The operator of the clinic wonders whether he can increase the efficiency of testing procedure by conducting pooled tests , the operator would pool the 50 blood samples and test them altogether. If the pooled tests was negative, he can pronounce each group healthy . If not , he could test them individually. The expected number of blood tests the operator will have to do if pools the blood samples

A 47

B 25

C 21

D None of these

iska bhi logic sir ke upar se gaya hai mere

solution OA 21
P(one person unhealthy) =1/100
In a group of 50 mem, number of unhealthy persons can be
0,1,2,3...50
their probability
P(0 unhealthy) =(0.99)^50
P(1 unhealthy) =(0.99)^49*(0.01)*50c2
...
....
...
..
p(50 unhealthy) 50c50 * (0.01)^50
when no person is unhealthy, test will be negative, hence in on test everyone will be declared healthy
in all other cases 50 + individual tests will be required
P(1 test is required) =(0.99)^50 =0.60
p(51 tests required) =0.4 (1-0.6)
so reqrd expectation = 1*0.6 + 51*0.4 = 21
:banghead:
@krum
924
@Ashmukh said:
A petrol tank at a filling station has a capacity of 400 litres. The attendant sells 40 litres of petrol from the tank to one customer and then replenishes it with kerosene oil. This process is repeated with six customers. What quantity of petrol will the seventh customer get when he purchases 40 litres of petrol?
40 *(0.729*0.729) ~ 40*(0.73*0.73) =40*(0.533) =21.32
925
@techsurge said:
solution OA 21P(one person unhealthy) =1/100In a group of 50 mem, number of unhealthy persons can be 0,1,2,3...50their probability P(0 unhealthy) =(0.99)^50P(1 unhealthy) =(0.99)^49*(0.01)*50c2............p(50 unhealthy) 50c50 * (0.01)^50when no person is unhealthy, test will be negative, hence in on test everyone will be declared healthyin all other cases 50 + individual tests will be requiredP(1 test is required) =(0.99)^50 =0.60p(51 tests required) =0.4 (1-0.6)so reqrd expectation = 1*0.6 + 51*0.4 = 21@krum
wah

@techsurge iift mien bas gadar questions hi ate hain kya? abhi tak ek bhi easy nai dekha
926
@krum said:
wah @techsurge iift mien bas gadar questions hi ate hain kya? abhi tak ek bhi easy nai dekha
last year easy tha 😃
927

An easy one:

For prime numbers A and B both greater than 3, what is the highest integer which divides A ˛ - B ˛ completely?

928
@vijay_chandola said:
An easy one:For prime numbers A and B both greater than 3, what is the highest integer which divides A ˛ - B ˛ completely?
24?
929
@vijay_chandola 24?
930
@vijay_chandola said:
An easy one:For prime numbers A and B both greater than 3, what is the highest integer which divides A ˛ - B ˛ completely?
24.
931
@vijay_chandola said:
An easy one:For prime numbers A and B both greater than 3, what is the highest integer which divides A ˛ - B ˛ completely?
24?
932
What is the number of non-negative integer solutions for the equation x^2 €“ xy + y^2 = x + y?
(a) 3 (b) 4 (c) 1 (d) None of these
933
Two mathematicians meet at a bar. After getting drunk A tells B, ” a,b,c are the sides of a triangle, c being the longest. If R is the circumradius of the triangle, a2+ b2= 2Rc”.
B replies ” Angle C is 90◦”. Then:
a) If A is right then B is right
b) If B is right then A is right
c) at least one is right
d) both of them are right
e) none of these
Approach plz.
934
@vijay_chandola said:
What is the number of non-negative integer solutions for the equation x^2 €“ xy + y^2 = x + y?(a) 3 (b) 4 (c) 1 (d) None of these
none of these...
x = 0 y = 1
x = 1 y = 2
x = 2 y = 1 , 2
y = 0 x = 1

935
@vijay_chandola said:
What is the number of non-negative integer solutions for the equation x^2 €“ xy + y^2 = x + y?(a) 3 (b) 4 (c) 1 (d) None of these
none...5
936
@vijay_chandola None of these.. 5 solns
937
@Anivesh90 said:
Two mathematicians meet at a bar. After getting drunk A tells B, ” a,b,c are the sides of a triangle, c being the longest. If R is the circumradius of the triangle, a2+ b2= 2Rc”.B replies ” Angle C is 90◦”. Then:a) If A is right then B is rightb) If B is right then A is rightc) at least one is rightd) both of them are righte) none of theseApproach plz.
b) ?
938
@vijay_chandola said:
What is the number of non-negative integer solutions for the equation x^2 €“ xy + y^2 = x + y?(a) 3 (b) 4 (c) 1 (d) None of these

(d) none of these..??
My first post one on this thread ....
939
@Anivesh90 said:
Two mathematicians meet at a bar. After getting drunk A tells B, ” a,b,c are the sides of a triangle, c being the longest. If R is the circumradius of the triangle, a2+ b2= 2Rc”.B replies ” Angle C is 90◦”. Then:a) If A is right then B is rightb) If B is right then A is rightc) at least one is rightd) both of them are righte) none of theseApproach plz.
if C=90
then R=c/2 or c=2*R

and a^2+b^2=c^2=c*2R

==> if B is right, then only A will be right.
So, option b?
940
@rkshtsurana nopes.. but approach?