Solution:

Let us assume,
the radius of the river is R.
the speed of beast is S.
the speed of duck is S/4.
Circumference = 2 * Pi * R.

Now, if duck swims R/4 distance from the center of the river and then begins to swim across the river in center implies both duck and beast can take the round trip in same time.
Explanation :
time by beast : 2 * Pi* R * S
time by duck : 2 * Pi* R/4 * S/4 => 2 * Pi* R * S


Now, the duck can move slowly inward toward the center of the river, and begin swimming around the center in a circle from this distance. It is now going around a very slightly smaller circle than it was a moment ago, and thus will be able to swim around this circle FASTER than the beast can run around the shore.

The duck can keep swimming around this way, pulling further away each second, until finally it is on the opposite side of its inner circle from where the beast is on the shore. At this point, the duck aims directly toward the closest shore and begins swimming that way. At this point, the duck has to swim [0.75R feet + 1 millimeter] to get to shore. Meanwhile, the beast will have to run R*pi feet (half the circumference of the river) to get to where the duck is headed.
The beast runs four times as fast as the duck, but you can see that it has more than four times as far to run:

[0.75R feet + 1 millimeter] * 4 < R*pi

[This math could actually be incorrect if R were very small, but, in that case, we could just say the duck swam inward even less than a millimeter and make the math work out correctly.]

Because the duck has less than a fourth of the distance to travel as the beast, it will reach the shore before the beast reaches where it is and successfully escape.

Solution:

Uncle Scrooge tells him he took the loan to keep his expensive car safe and he also saves money on security and parking rent.

Solution:

SC

12 zodiac signs are : Aries Taurus Gemini Cancer Leo Virgo Libra Scorpio Sagittarius Capricorn Aquarius Pisces

Solution:

I am word "Introvert"

Solution:

-3 -1 1

Explanation:
-3 * 1 * -1 = 3(prime)
-1 - (-3) = 1 -(-1) = 2

Solution:

6:35 pm

Explanation:
Time of Frank Lampard last missed plane = 7:00 p.m - 50 min = 6:10 p.m
As this information has been given to Frank Lampard 15 minutes after the plane has already left, the air hostess gave the information at 6:10 p.m + 25 min = 6:35 p.m

Solution:

As we have been informed that the prices are a full dollar increment, this eases out the situation.

If we look at the price of pineapple and capsicum, we can easily make out that both of them are priced $1.
This is because the price has to be at least $1 and since both of them costs $2 together, they must cost $1 separately.

Solving the rest of the question is child’s play. You have to use simple mathematics.

For an instance:
Jalapeno + Pineapple = $5
Now, we know that pineapple costs $1. Thus,
Jalapeno + $1 = $5
Jalapeno = $4

You can find out the price for each one of the toppings in a similar fashion.
Capsicum $1
Pineapple $1
Mushrooms $3
Corn $2
Jalapeno $4
Red Pepper $2
Black Pepper $3
Olives $4

Solution:

20741616380

Explanation:
5 * 5 - 5 =>20
20 * 20 - 20 => 380
380 * 380 -380 =>144020
144020 * 144020 - 144020 => 20741616380

Solution:

Yes, show in below picture

Solution:

Let us try to find average here.
The average number of hands per person among the people with one hand is 1 obviously.

Now in the remaining slot, half people have 1 arm and half have 2 arms. Therefore, the average arm per person is 1 only.

Now, if we combine both the results, we can conclude that the number of arms per person in that locality is 1.

Since the number of people living there is 200 in number, the number of arms will be 200 as well.

Solution:

1

Explanation:
4 + 9 = 1
The trick to solve is to assume the first number as the time in AM and the second number is the number of hours you have to add to it. You'll find the time in PM when you do that.

For example
7 AM + 7 hours = 14:00 or 2 PM

4 AM + 9 hours = 13:00 or 1 PM.

Solution:

"World War I" was named after after "World War II"

Solution:

common sense

Explanation :
We can break it into the following three parts
ITIT
,N
CENTCENT

Now ITIT = 2 Its which can be molded into IT's
,N = Comma + N which can be molded into Common
CENTCENT = 2 Cents which can be molded into Sense

So, the letters basically represent:
It's common sense.

Solution:

Were you able to do it under two minutes? The words that will be formed are as below:
Friend
Society
Alien
Stymie
Shriek

Solution:

151 (131+20)

Explanation:
1st 7 prime numbers post 100 are
101 , 103 , 107 , 109 , 113 , 127 , 131
...Adding 20 to numbers
121 , 123 , 127 , 129 , 133 , 147 , 151

Solution:

The murderer is Marcus.

The notes hinted towards the name of Marcus. How?
Just take the first letter from Compound, Art Room, Restroom, Underwater Room, Study Room and Movie Room and you will get:

C, A, R, U, S and M.

Rearranging these words leads to the name Marcus who is the murderer.

Solution:

Peter will have to use a lock box that can hold two locks. He will put the ring in a box and will mail it to Mary. Upon receiving the box, Mary will put her own lock box inside and will send back to Peter. Peter can then-then take off his lock and send it off to Mary again.

Solution:

She was not able to find 11 on phone.

Solution:

The driver is actually the wife and mother.

Solution:

in between job