Official Quant thread for CAT 2013

MBA CAT 2024
17886
@ani6 said:
iPuys,plz solve this ques :Q. Brass is an alloy of copper & zinc .Bronze is an alloy containing 80% of copper,4 % of zinc and 16% of tin.A fused mass of brass & bronze is found to contain 74% of copper ,16% of zinc,and 10% of tin.The ratio of copper to zinc in Brass is :a)64% & 36% b)33% & 67% c)50% & 75% d)35% & 65% e)none of these
64% & 36%
17887
@mbajamesbond said:
677 has exactly 5 digits when converted into base 'n' from the decimal system. What is the minimum possible value of 'n'?
677 in base 4 is 22211 and 200102 in base 3....hence 4 must be the answer..
17888
@mbajamesbond plz give the approach...

17889
@ani6 said:
@mbajamesbond plz give the approach...
Now we have a for fuse of alloy let it be 100 gm
so it contain..
copper 74 gm(coming from both)
zinc 16%(both)
10 gm Tin(coming from Bronze as it contain tin_)
now 100 gm Bronze gives 16gm tin..
=>100/16*10 gm will give 10 gm tin..
so 62.5 gm of bronze is used..
so it give 4%zinc=62.5*0.04=2.5gm
and 74% cu=50gm
So total Cu in fuse
74gm.(out of which 50gm from bronze)
=>24 gm from Brass
and 16-2.5=13.5gm Zinc from Brass..
so total weight used 37.5 gm of brass
hence after calutaing %gs we get
(A)A66% 36%
17890
ďťż
@Logrhythm said:
677 in base 4 is 22211 and 200102 in base 3....hence 4 must be the answer..
@saurav205 said:
n= 4??
OA 4
17891
'M' and 'N' are natural numbers such that by M = (5N – 4) (5N + 1). If what is the harmonic mean of all the possible values of M?

(200)^2/1001

1001

1001/(200)^2

1/1001

Edited with options.
17892
@mbajamesbond
5
17893
@anantn said:
@mbajamesbond5
For which ques?
17894
@saurav205 said:
at the request of@DeAdLy :A positive integer is written on each faces of a cube. At each corner (vertex) of the cube, the product of the numbers on the faces that meet at the corner is written. The sum of the numbers written at all the corners is 2431. Find the sum of the numbers written on all the faces of the cube?OA by midnight courtesy Test Funda sorry if this question has already been posted by someone else...
mere liye specially...

chalo fir to answer bi batana padega..41
17895
@mbajamesbond said:
'M' and 'N' are natural numbers such that by M = (5N – 4) (5N + 1). If what is the harmonic mean of all the possible values of M?
Is it 1001??
HM of all M means AM of all 1/M...
1/M = 1/{(5N-4)(5N+1)}
Sum(1/M) = S(5/M) = 1/(5N-4) - 1/(5N+1) = 1 - 1/6 + 1/6 - 1/11 + 1/11 - .... - 1/996 + 1/996 - 1/1001 = 1 - 1/1001 = 1000/1001
S(1/M) = 200/1001
so, HM(M) = 200/(200/1001) = 1001...

17896
@ani6 said:
iPuys,plz solve this ques :Q. Brass is an alloy of copper & zinc .Bronze is an alloy containing 80% of copper,4 % of zinc and 16% of tin.A fused mass of brass & bronze is found to contain 74% of copper ,16% of zinc,and 10% of tin.The ratio of copper to zinc in Brass is :a)64% & 36% b)33% & 67% c)50% & 75% d)35% & 65% e)none of these
64% and 36%?

brass------> C.....z
bronze----> C.....z......t----->80%.....4%....16%
alloy------->C......Z.....t----->74%.....16%...10%

let alloy be 1000kg.....so ratio = 740:160:100
now this 10% of tin came from 16% of tin in bronze
so amount of tin in bronze = 100 kg
therefore ratio of c:z:t in bronze = 500:25:100
amount of copper in brass = 740 - 500 = 240------64%
amount of zinc in brass = 160 = 25 = 135----->36%
17897
@vbhvgupta said:
Q4
sarkkaar 12 days hai kya answer??
17898
@DeAdLy said:
sarkkaar 12 days hai kya answer??
12..smajha do
17899
@mbajamesbond said:
'M' and 'N' are natural numbers such that by M = (5N – 4) (5N + 1). If what is the harmonic mean of all the possible values of M?(200)^2/100110011001/(200)^21/1001Edited with options.
@Logrhythm Oa 1001
17900
@vbhvgupta said:
12..smajha do
lo fir..
75% work main to X-10 lagte.
so 100% main 4(X-10)/3
therefore ek aadmi- 4(X-10)/3(X+7)
also pehle condition se ek aadmi- X/X-2
dono ko equate karo..solve karo X ke liye

X+10 matlab total 30.

So substitue karo pehle condition main aur days aaye 12...
17901
how many different 7-digit numbers are there the sum of whose digits are odd?
(a)45.10^5
(b)24.10^5
(c)224320
(d)None of these
guys please post the solution.answer given is (a)
17902
@ani6 said:
iPuys,plz solve this ques :Q. Brass is an alloy of copper & zinc .Bronze is an alloy containing 80% of copper,4 % of zinc and 16% of tin.A fused mass of brass & bronze is found to contain 74% of copper ,16% of zinc,and 10% of tin.The ratio of copper to zinc in Brass is :a)64% & 36% b)33% & 67% c)50% & 75% d)35% & 65% e)none of these
A=64 & 36%
17903
@tshaik said:
how many different 7-digit numbers are there the sum of whose digits are odd?(a)45.10^5(b)24.10^5(c)224320(d)None of theseguys please post the solution.answer given is (a)
total number of 7 digit numbers = 9*10^6
half of these would have odd sum of digits = 45*10^5....
17904
@vbhvgupta said:
Q 5
45
17905

how many 6-digit numbers contain exactly 4 different digits?

(a)4536

(b)294840

(c)191520

(d)None of these

Guys please post the solution,answer given is (b)