A balanced coin will have 50:50 chance of showing either head or tail. In this question, you are asked the probability to find the first head after two tosses. That means the toss result should be:
1. tail = 1/2 probability
2. head = 1/2 probability
Previously you are tossing the coin 10 times and obtain zero head. But this previous 10 tosses result should not influence your probability in the 11th and 12th toss. The chance will always be 50:50 no matter how much the tosses count. So the probability should be: 1/2 * 1/2= 1/4
Velocity of the ring wraiths relative to the air:
The speed 
is what we want to find - this is the speed at which the wraiths are flying in the air.
(Note: 
denotes velocity, while 
denotes speed)
Velocity of air relative to the ground:
The ring wraiths want their trajectory to be due north, which means their velocity relative to the ground should be
To an observer on the ground, 
is the speed at which the wraiths would appear to be moving in the air.
The relative velocities satisify
Answer: C :D
Step-by-step explanation:
4m^4-5m^2
Basically you divide each term by the denominator
this is akin to splittting fraction. Just as you can add 2/5 and 4/5 to get (2+4)/5, like wise you can split apart fractions. By doing this, you get two fractions and you can evaluate them individually
