Official Quant thread for CAT 2013

MBA CAT 2024
12581
@nramachandran said:
Angle covered by the hour handAt 4 o clock, anggle = 4*30 = 120At 4:16, additional angle covered = 120 +(16*0.5) = 128 This is because hour hand covers 0.5 degree each minute, so in 16 minutes it covers an additional 8 degreesAngle covered by minute hand = 16*6 = 96Angle between them = 128-96 = 32 degrees
at 4'o clock angle was 120 b/w hour hand and min hand
in 16 min minute hand moves=6*16=96 degrees
i.e. 120-96 wrt hour hand
in same time hour hand moves=0.5*16=8 degrees
hence angle=24+8=32 degrees
12582

@ravi.theja said:
You have enough coins of 1, 5, 10, 25 paise. How many combinations are possible to make 50 paise?a) 52b) 49c)44d) 45
let no. of coins of
1 paisa=a
5 paisa=b
10 paisa=c
25 paisa=d

so, a+5b+10c+25d=50

here a must be divisible by 5, so let a=5a'
a'+b+2c+5d=10 (all >=0)
when d=0, 11+9+7+5+3+1=36 solutions
d=1,6+4+2=12
d=2, 1 solution

total=49
12583

A person has a total of rs.210 in one rupee, 50 paise and 25 paisa coins. The values of the three type of coins the person had were in the ratio 2.5: 3: 4 repectively.

How many one rupee coins the person has????????????
12584

A person has a total of rs.210 in one rupee, 50 paise and 25 paisa coins. The values of the three type of coins the person had were in the ratio 2.5: 3: 4 repectively.

How many one rupee coins the person has????????????
12585

A person has a total of Rs.210 in one rupee, 50 paise and 25 paisa coins.
The values of the three type of cins the person had were in the ratio 2.5 : 3 : 4 respectively.
How many one rupee coins the person has??????

12586
@bs0409
let no. of coins of1 paisa=a5 paisa=b10 paisa=c25 paisa=dso, a+5b+10c+25d=50here a must be divisible by 5, so let a=5a'a'+b+2c+5d=10 (all >=0)----> sir ye thought process kaise generate kiya??when d=0, 11+9+7+5+3+1=36 solutions----->d=1,6+4+2=12d=2, 1 solutiontotal=49
sir plz explain part in bold
12587

Q. The probablity of a bomb hitting bridge is 0.5 and two direct hits are required to destroy it. Find the least number of boms required so that probablity of the bridge being destroyed is 0.9
a) 11
b) 10
c) 9
d) 8

12588
@sahil.oberoi 105




12589
@bs0409 pls xpln clearly 😃 :poor me :
12590
@Highway66 said:
@bs0409let no. of coins of1 paisa=a5 paisa=b10 paisa=c25 paisa=dso, a+5b+10c+25d=50here a must be divisible by 5, so let a=5a'a'+b+2c+5d=10 (all >=0)----> sir ye thought process kaisegenerate kiya??when d=0, 11+9+7+5+3+1=36 solutions----->d=1,6+4+2=12d=2, 1 solutiontotal=49 sir plz explain part in bold
first part=experience
second part=I did it mentally. will not take more than 1 minute.
12591
@ravi.theja A) 11??
12592
@insane.vodka said:
Answr is correct..please post the solution as well!!!!!!!!!!!!!
12593
@sahil.oberoi 105 😃 1.a+ 1/2*b +1/4* c = 210... ==> a=2.5 X b=3X c=4X ==> 5X=210 ==> x=42 ==> a = 42*2.5 = 105
12594
@insane.vodka ans nahi pata bhai 😞 sry method pucho..ll discuss
12595
@sahil.oberoi

ratio is 2.5: 3 : 4
that means for every
2.5 of 1rs, 1.5rs of 50p and 1rs of 25p coins
i.e.
for every
2.5rs of 1rscoin there are 2.5rs of 50p and 25p coins
so 1/2 of 1rs coin and 1/2 of 50p and 25p coins
so out of 210rs 105 will be 1rs coins
12596
@ravi.theja said:
@sahil.oberoi 105 1.a+ 1/2*b +1/4* c = 210... ==> a=2.5 X b=3X c=4X ==> 5X=210 ==> x=42 ==> a = 42*2.5 = 105
Yaa a:b:c = 2.5 : 3: 4 hai...
a= 2.5 X kaise hua...???
a/b...b/c kaise nikalte hai????
12597
@sahil.oberoi said:
Yaa a:b:c = 2.5 : 3: 4 hai...a= 2.5 X kaise hua...???a/b...b/c kaise nikalte hai????
@sahil.oberoi no.of 50p coins are 3X so money is 1.5X only...similarly 4X is no. of coins Xrs
12598
@ravi.theja im gettin 7..
P(H)=1-P(doesnot get hit)-p(hit in one)
for n=7 space=2^7
P(h)=1-(7C1+1)/128
p(h)=0.92 (app)
12599
@insane.vodka said:
@sahil.oberoiratio is 2.5: 3 : 4that means for every 2.5 of 1rs, 1.5rs of 50p and 1rs of 25p coinsi.e.for every2.5rs of 1rscoin there are 2.5rs of 50p and 25p coinsso 1/2 of 1rs coin and 1/2 of 50p and 25p coinsso out of 210rs 105 will be 1rs coins
Method jugaadu hai par badiya hai....!!!!!!!!
Thanks...
bht basic questns puch rha hun...
abi start ki hai prep...working rite now!!!!!!!!
12600

dats y it becomes 5X bhai... 2.5 X *1 + 3X *0.5 + 4X* 0.25 = 5x @sahil.oberoi