Red Whale Interview Questions, Process, and Tips

option 5

Let ‘x’ be the number of perons in the group and let ‘y’ be
amount per head which they have to pay.
Then xy = 2400.
or y = 2400/x
Since two friends have forget the purse, x-2 persons should
share the total amount(2400).
If they share, they have to make an extra contribution of
Rs 100 to pay up the bill
That is x-2 persons should pay y+100 each
or (x-2)(y+100) = 2400
or y+100 = 2400/(x-2)
or y = 2400/(x-2) – 100
Therefore we have got two equations namely,
y= 2400/x and y = 2400/(x-2) – 100
Comparing these two, we get
2400/x = 2400/(x-2) – 100
Solving this we get
x^2 – 2x -48 = 0
or (x-8) (x+6) = 0
or x = 8 or x = -6
Since ‘x’ denote the number of persons, it should be
positive.
So, x = 8.

C. 20

One day work = 1 / 20
One mans one day work = 1 / ( 20 * 75)
Now:
No. Of workers = 50
One day work = 50 * 1 / ( 20 * 75)
The total no. of days required to complete the work = (75 * 20) / 50 =
30

117000

1(100-1)+ 2(100-2)+…..99(100-99)
N=100
solution: N(N-1)
100(99)= 9900

350m

192 Zeroes

1) time =20mins,speed=15kmph=15*(5/18)=25/6 m/sec
distance=20*(25/6)=250/3 m
then 2) given as time =15min
speed=250/3*15=(50/9)*(18/5)kmph=20kmph

9000

3630

Alice — 3844
Liu —30976

In the example first we have to find the area of the field

we have given the following values ,

cost of fencing per meter = Rs 1.50

Diameter of circular field = 28

We have to find the area , a = ?

We know that,

Area = 2 π r

= 2 x 22/7 x 14

= 2 x 22 x 2

= 44 x 2

= 88 sq. m

So, area of circle is 88 sq.m

Now just multiply it with 1.50

cost of fencing = 88 x 1.50

= Rs. 132

So, the cost of fencing the circular field is Rs. 132

D. Vice President