St. christopher's school Interview Questions, Process, and Tips

Answer: Pile II

Explanation:

72 — 9
? —- 1

=> Down Stream = 8

45 —- 9
? —- 1

=> Up Stream = 5

Speed od current S = ?

S = (8 – 5)/2 = 1.5 kmph.

question is incomplete

p = prob(1st digit not 7)*prob(2nd digit not 7)*prob(3rd
digit not 7)
=(8/9)*(9/10)*(9/10)
=0.72
Sandhya had it right except that there are 900 numbers
between 100 and 999 inclusive (not 899).

The probability will be
white ball = 5/9
red ball = 4/9
The answer can be 5/9 and 4/9 or 1

Let the distance between each pole be x m. Then, distance up to 12th pole = 11x m

∴ Speed = 11x22m/s

∴ Time to cover total distance up to 20th pole

= 19x×2411x

= 41.45 s

c

Y

divide 100 by 7, and you get 14.28. (Obviously you aren’t talking about decimals here) and so 14 numbers can be divisible by 7 up to 100.

The answer is 14.

five multiplication & three addtion

167

these are question tht are seem to be like it consumes
time. so dont see jus the question and run to the next .

ans. a) 12

if 9 balls are added then the ratio to the combination
becomes 2:4:3.

9 balls make the ratio 3 for grey balls in tht mixture.
so the factor is 9/3 = 3 (in tht mixture)

so the same factor has to be maintained through out the
ratio. so black balls is 4 * 3 = 12 and white balls is 2 *
3 = 6.

C)1440
2*2=4
4*3=12
12*4=48
48*5=240
240*6=1440

I solve it as the 280m train being stationary… and the 120m train moving at (42+30) = 72kph…. or 20mps

The front of the train will have to go 280m to pass the stationary train plus another 120m for the backs to clear… that is 400m in all.

The time to travel 400m at 20mps is 20secs

Out of 10 persons, 4 are graduates; so, (10 – 4) = 6 are under-graduates.

If there is no restriction, any three can be chosen from the ten in (10C3) = 120 ways.

Now, if all three chosen are under-graduates; it can take place in (6C3) = 20 ways.

Therefore, the probability that there will be no graduate among the three chosen = (20 / 120) = (1 / 6).

Therefore, the probability that there will be at least one graduate among the three chosen = {1 – (1 / 6)} = (5 / 6) = 0.8333.