This is sort of simple. 2 grams of X can combine with 4 grams of Y to form XY. Y is 2 times the amount of grams in X. So if there are 11 grams of X there are 22 grams of Y to form XY. Or you could take 11 divided by 2 is 5.5 and then multiply 4 by 5.5 to get 22. If this is wrong please tell me I would be very happy to know.
Answer: Gamma rays
Explanation: The given waves belong to the electromagnetic spectrum which consists of different electromagnetic radiations arranged in terms of increasing wavelengths or decreasing frequencies.


Thus 
E= energy
= frequency
c = speed of light
= wavelength
Thus frequency and wavelength are inversely related. The waves having high energies ave high frequencies and have shorter wavelengths.
Thus gamma rays having highest energy have highest frequency and shortest wavelength.
Answer:
The final velocity of the cart is
Explanation:
From the question we are told that
The mass of the girl is 
The mass of the cart is 
The speed of the cart and kid(girl) is 
The final velocity of the girl is 
Let assume that velocity eastward is positive and velocity westward is negative (Note that if we assume vise versa it wouldn't affect the answer )
The total momentum of the system before she steps off the back of the cart
is mathematically evaluated as

substituting values


The total momentum after she steps off the back of the cart is mathematically evaluated as

Where
is the final velocity of the cart
substituting values


Now according to the law of conservation of momentum

So

=> 
Since the value is positive it implies that the cart moved eastward
To solve this problem we will use the linear motion description kinematic equations. We will proceed to analyze the general case by which the analysis is taken for the second car and the tenth. So we have to:

Where,
x= Displacement
= Initial velocity
a = Acceleration
t = time
Since there is no initial velocity, the same equation can be transformed in terms of length and time as:

For the second cart

When the tenth car is aligned the length will be 9 times the initial therefore:

When the tenth car has passed the length will be 10 times the initial therefore:

The difference in time taken from the second car to pass it is 5 seconds, therefore:

From the first equation replacing it in the second one we will have that the relationship of the two times is equivalent to:


From the relationship when the car has passed and the time difference we will have to:



Replacing the value found in the equation given for the second car equation we have to:

Finally we will have the time when the cars are aligned is


The time when you have passed it would be:


The difference between the two times would be:

Therefore the correct answer is C.
The initial velocity (its speed before falling off) is approximately 1.95 m/s