Official Quant thread for CAT 2013

MBA CAT 2024
18166
@Jackson1 said:
Distance travelled by train in 8 min= Distance travelled by bullet in 2 minso x*8=300*2x=75 m/s..
@junefever said:
confused....
ahh...i knw ur confusion...the distance keeps on decreasing...it is not constant so that is why the answer wld not be 75..and i m sure 75 wld hv been in the options..
18167
@Logrhythm said:
ahh...i knw ur confusion...the distance keeps on decreasing...it is not constant so that is why the answer wld not be 75..and i m sure 75 wld hv been in the options..
got the point, was not considering that distance is also decreasing...
18168
@saurabhlumarrai said:
@junefever@mailtoankit@Jackson1 answer is 60mpsThe conceptual mistake which everone is making is considering the distance to be constant,which is not the case.The distance keep on decreasing as the train is moving.Normal Approach:10/60=d/300 =>d=50again,8/60=d/300+x =>x=75But the approach is wrong- It should be10/60=d/300 =>d=50again,8/60=(d-x*(2/60))/(300+x) => x=60
See my concept...mohan hears first bullet..now if the train does not move then mohan hears the 2nd bullet after 10 min but train is moving so he hears the bullet after 8 min..so the distance travelled by train in 8 mins would definately be equal to the distance travelled by bullet in 2 mins...
18169
@Jackson1 said:
See my concept...mohan heards first bullet..now if the train does not move then mohan heards the 2nd bullet after 10 min but train is moving so he heards the bullet after 8 min..so the distance travelled by train in 8 mins would definately be equal to the distance travelled by bullet in 2 mins...
boss,
ur concept is correct with a slight modification that distance travelled by train in 10 min=distance travelled by bullet in 2 min.
Then only you would get the correct answer.
18170
@saurabhlumarrai said:
boss,ur concept is correct with a slight modification that distance travelled by train in 10 min=distance travelled by bullet in 2 min.Then only you would get the correct answer.
bro mohan is in the train and he is listening the sound of 2nd bullet after 8 mins so obviously train has also moved for 8 mins and not 10 mins..
18171
Right triangle PQR is to be constructed in the xy-plane so that the right angle is at P and PR is parallel to the x-axis. The x and y coordinates of P, Q and R are to be integers that satisfy the inequalities -4
18172


There are 3 white balls and 4 black balls in a bag, and a set S = {0, 1}. Now one ball is chosen from the bag and if it's white then the set S remains the same and if the ball chosen is black then the element '1' is replaced by '–1' in the set S. After choosing one ball and fixing the set S, three numbers α, β, γ (not necessarily distinct) are chosen from the set S. Then what is probability of having real and finite number of solutions of the equation x^α + x^β + γ = 0
OPTIONS

1)
2)
3)
4) None of the above
18173
@pirateiim478 said:
Right triangle PQR is to be constructed in the xy-plane so that the right angle is at P and PR is parallel to the x-axis. The x and y coordinates of P, Q and R are to be integers that satisfy the inequalities -4
10C2*10*2*11=9900?
18174
@vbhvgupta said:
Q4
bhai alok sachin wale ka answer 60 hai kya?

18175
@pakkapagal said:
bhai alok sachin wale ka answer 60 hai kya?
yes, 60 it is.
18176
@vbhvgupta Answer 75hai......cl ke test series ka sawaal hai
18177
@raj37 said:
@vbhvgupta Answer 75hai......cl ke test series ka sawaal hai
nahi yar. Q is from TIME material.
if it is so thn cl is giving time's q in their mocks
18178

Yaar physics lga k bhi dekh li....time coordinates se....ans75 hi aarha hai

18179
@raj37 said:
Yaar physics lga k bhi dekh li....time coordinates se....ans75 hi aarha hai
yar tum alok sachin vala hi solve kar rahe ho na??????
18180

Bhai ankit hai vo sorry.....guns vala question tha

18181
@vbhvgupta said:
nahi yar. Q is from TIME material.if it is so thn cl is giving time's q in their mocks
bhai konsa question hai?? muje bhi do....yahan bore ho gaye hai...
18182
@chandrakant.k said:
let vivek work 60 units ram work 90 and bhuvan 150Their rate are in the ratio 1:2:3Vivek takes 12 days which means he does 5units of work per daySo ram does 10 units and bhuvan does 15units per dayso in 8 days vivek does = 5*8 = 40ram = 10*8 = 80bhanu = 15*8 = 120total work done = 240total work to be done = 150+90+60 = 300so amount of work done = 240/30 = 4/5
according 2 question,is it nt given dat vivek takes 12 days 2 complete d entire work,say 300 in ur case..in dat case d 0A sud b different?
18183
@ani4588 said:
Consider the houses a x x x x x x x x x x in a row. Now consider he chooses any of the houses which i will indicate by '+' signs.x + x x + x x x + x (Selected houses are replaced by '+')Formulating same as Permutation,A+B+C+D = 7 [Not 10 excluding the 3 selected houses]Now A and D can be zero i.e. whole numbers.But B and C must be at least 1 i.e. natural numbers.Now the equation will be a + b + c + d = 5 and number of solutions will be C(8,3) = 8*7*6/1*2*3 = 8*7 = 56@abhishekhenry
plz share how to formulate this type of equation a+b+c+d =7 , i am unable to understand it
18184
@mohitjain said:
according 2 question,is it nt given dat vivek takes 12 days 2 complete d entire work,say 300 in ur case..in dat case d 0A sud b different?
it is given that 12 days to complete his part which is 60 units of work .
18185
@raopradeep said:
plz share how to formulate this type of equation a+b+c+d =7 , i am unable to understand it
if a,b,c and d can be 0 so there is a direct formula for that- C(7+4-1,4-1)=C(10,3)
here 7 is sum of all the numbers and 4 is the number of variables..