Cogent infotech Interview Questions, Process, and Tips

Let n be the number of days it takes A and B, working together, to finish. And we know B=A+10 and B=3A, so:

3A=A+10

2A=10

A=5

Then B=15

So:

1/A + 1/B=1/n where n is the total amount of days. So:

1/5 + 1/15=1/n

3n+n=15

n=15/4 days

Before Swapping
_ _ _ _ _ _ _ Shilpa ……..Reena _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

After Swapping
_ _ _ _ _ _ _ Reena _ _ _ _ _ Shilpa _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
—————————–>14=17 <——————————-

So total number of girls in that row are 30

( d ) Cannot be determined

1.5 km/hour

cut a sphere in all 3 axis with center point as common point
of all axis.
u would be getting 2 lines and an arc
in other words
sphere is cut into 3 cuts in x,y,z directions
it is only similar

3 hours ago.

Thin candle melts 3/4 in 3 hours leaving 1/4
Where as in the same time thick candle melts 3/6 leaving 3/6 which is 1/2. Now thick candle is exactly twice than the thin candle.

Or via modeling:

We need to find time at which the length of the thin candle is half the thick candle. Let x be the time. Thin candle melts at 1/4 an hour and thick candle melts at 1/6 an hour. In x hours they melt at x/4 and x/6 respectively. What’s left will be 1 – x/4 and 1 – x/6. We need to find x at which :

2 * (1 – (x/4)) = 1 – (x/6)

This equation results in x = 3

31.6%
100-20%=80
80-10%=72
72-5%=68.4
100-68.4= 31.6%

East

B. 9001

if rs 12 and rs 15 per meter then 750*12+750*15

13. One group of each = 2+3+5 = 10 and 1 remainder for each = 1+1+1 = 3. 10+3 = 13

Correct option is C)
Let be students are consider as child
Let the age of child added later be x years.
average age of 12 children =20 years
∴ Total age of 12 children =20×12=240 years
After one more child is added-
Average of 13 children =20−1=19 years
Average age of 13 children =
13
sum of 12 children+x
​

19=
13
240+x
​

⇒240+x=247
⇒x=247−240=7 years
Hence the age of child added later is 7 years.