Official Quant thread for CAT 2013

MBA CAT 2024
16786

The present worth of a certain bill due sometime hence is Rs. 800 and the true discount is Rs. 36. The banker's discount is:
A. Rs. 37
B. Rs. 37.62
C. Rs. 34.38
D. Rs. 38.98

16787
@ananyboss said:
Find the Three digit number ?it is known that the sum of digits is 17.sum of squares of the digit is 109If we subtract 495 from the number, we obtain a number consisting of same digits written in reverse.I am not asking for this particular question, but i want to know the approach./ concept of solving these questions. Please helpThanks in advance
a+b+c = 17 .

a^2 +b^2 +c^2 = 109.

abc -495 = cba ==> 100a+10b+c -495 = 100c + 10b +a

==> 99a - 99c = 495 ==> a-c = 5 ==> c = a+5

a+b+a+5 = 17 ==> 2a +b = 12 ==> b = 12 - 2a ;

a^2 + (12 - 2a)^2 + (a+5)^2 = 109 ==> on solving the equation ==> a= 3, 10/3 . it has to be a integer so a=3

===> c= 8 and b = 6 number is 368 / 863 ... Generally for this kind of problems going from options is the best way

16788
In an examination having 2 sections, a student gets 90%ile in each section. What can be the overall maximum and minimum %ile of the student?
16789
@techgeek2050 said:
In an examination having 2 sections, a student gets 90%ile in each section. What can be the overall maximum and minimum %ile of the student?
min 0 and max 100 :P
16790
@ravi.theja said:
min 0 and max 100
min is 80 , max 100
what 's ur approach?
16791
@techgeek2050 said:
min is 80 , max 100what 's ur approach?
for max..i took like..evry one getng more dan him in one section gets less in other section..so that his total is the highest and he gets a 100 %ile....

and min case ..no idea..
16792
@techgeek2050 said:
In an examination having 2 sections, a student gets 90%ile in each section. What can be the overall maximum and minimum %ile of the student?
90 behind him in Sec1, 90 in sec2..So a maximum of 20 out of 100 can be ahead of him.
Min %ile = 80
Max = 100
16793
@The_Loser said:
in a room ther are 7 persons. the chances that two of them were born on the same day of week.?
Not getng birthdays on same day = 1 - 7! / 7^7 ..jus like arranging 7 members
16794
The remainders when F(x) is divided by x - 99 and x - 19 are 19 and 99, respectively. What is the remainder when F(x) is divided by (x - 19) (x - 99)?
16795
@ishu1991 said:
The remainders when F(x) is divided by x - 99 and x - 19 are 19 and 99, respectively. What is the remainder when F(x) is divided by (x - 19) (x - 99)?
Remainder has always 1 degree less that quotient
F(x) is divided by (x-19)(x-99) =>remainder is degree1 =>bx+c

F(x)=a (x-19)(x-99) ďťż+bx+c
F(19)=19b+c=99
F(99)=99b+c=19
solve=>b=-1 c=118

bx+c=-x+118
16796
@naveenkrs ok
16797
The amount used to purchase 1ltr of petrol can be used to purchase 3ltrs of diesel or 5 ltrs of kerosene.Out of a certain amount,Rs 510 is spent on diesel.

How much is spent on kerosene if equal volumes of the 3 liquids are purchased with the total amount?

A) 300
B) 306
C) 382
D) 354

What will be the amount spent on petrol if the total amount referred in the above question,is instead spent to purchase equal volumes of petrol & kerosene?

A) 1250
B) 1275
C) 1955
D) 1360
16798
@bs0409 said:
The amount used to purchase 1ltr of petrol can be used to purchase 3ltrs of diesel or 5 ltrs of kerosene.Out of a certain amount,Rs 510 is spent on diesel.How much is spent on kerosene if equal volumes of the 3 liquids are purchased with the total amount?A) 300B) 306C) 382D) 354What will be the amount spent on petrol if the total amount referred in the above question,is instead spent to purchase equal volumes of petrol & kerosene?A) 1250B) 1275C) 1955D) 1360
ans 1) b. 2)c.
16799
@iLoveTorres said:
ans 1) b. 2)c.
Right.....
Show working plz....
16800
@bs0409 said:
The amount used to purchase 1ltr of petrol can be used to purchase 3ltrs of diesel or 5 ltrs of kerosene.Out of a certain amount,Rs 510 is spent on diesel.How much is spent on kerosene if equal volumes of the 3 liquids are purchased with the total amount?A) 300B) 306C) 382D) 354What will be the amount spent on petrol if the total amount referred in the above question,is instead spent to purchase equal volumes of petrol & kerosene?A) 1250B) 1275C) 1955D) 1360
relative rates of petrol:diesel:kerosene :: 15:5:3

1) So if 510 is spent on diesel then 1530 is spent on petrol and 306 on kerosene

2) If total amount = 153+510+306=2346 is spent only on petrol and kerosene, then the ration will be 5:1 => petrol = (5/6)*2346 = 1955
16801
@naveenkrs said:
relative rates of petrol:diesel:kerosene :: 15:5:31) So if 510 is spent on diesel then 1530 is spent on petrol and 306 on kerosene2) If total amount = 153+510+306=2346 is spent only on petrol and kerosene, then the ration will be 5:1 => petrol = (5/6)*2346 = 1955
EXXAGTLY :P
16802
@bs0409 said:
The amount used to purchase 1ltr of petrol can be used to purchase 3ltrs of diesel or 5 ltrs of kerosene.Out of a certain amount,Rs 510 is spent on diesel.How much is spent on kerosene if equal volumes of the 3 liquids are purchased with the total amount?A) 300B) 306C) 382D) 354What will be the amount spent on petrol if the total amount referred in the above question,is instead spent to purchase equal volumes of petrol & kerosene?A) 1250B) 1275C) 1955D) 1360
306,1955?

1). cost of 1 lt petrol = x ----> cost of n lt petrol = nx
cost of 3 lt diesel = x ----> cost of 1 lt diesel = x/3 ------> cost of n lt diesel = nx/3
similarly cos t of 5 lt kerosene = nx/5

let the total cost be y

(xn/3)*(y)/(xn + xn/3 + xn/5) = 510
y = 2346

so cost of kerosene
(xn/5)*2346/(xn + xn/3 + xn/5) = 306

2). cost of petrol = (xn)*2346/(xn + xn/5) = 1955


16803
@bs0409 said:
The amount used to purchase 1ltr of petrol can be used to purchase 3ltrs of diesel or 5 ltrs of kerosene.Out of a certain amount,Rs 510 is spent on diesel.How much is spent on kerosene if equal volumes of the 3 liquids are purchased with the total amount?A) 300B) 306C) 382D) 354What will be the amount spent on petrol if the total amount referred in the above question,is instead spent to purchase equal volumes of petrol & kerosene?A) 1250B) 1275C) 1955D) 1360
1. 1 lit petrol = a

1 lit diesel = a / 3

1 lit kerosene = a/5

let X liters of each be purchased ;

given ==> X * a/3 = 510 ==> a*x = 510 * 3

need to find a/5*x = 510/5 * 3 = 102 * 3 =306.

2. Total amount in above case = 510*3 + 510 + 306 = 2346.

Now if its spent on kerosene and petrol => a.x + a.x/5 = 2346 ==> a.x = 1955
16804
what would be the LCM of 3333....3 (written 70 times) and 2222....2(written 20 times)?
16805
@TootaHuaDil said:
what would be the LCM of 3333....3 (written 70 times) and 2222....2(written 20 times)?
66666....666 written 140 times