For the first digit you are choosing from 2 digits
for the second digit you are choosing from 2 digits
for the third digit you are choosing from 2 digits
2*2*2=8
111
110
011
101
000
001
100
010
However......
A number doesn't usually start with a 0 or 0s.
Therefore, if you want 3-digit numbers and not just permutations using 0 and 1, then you must eliminate
011, 000, 001, and 010
Seeing that the first digit can't be 0, you choose from 1, then 2, and then 2 digits again; 1*2*2=4 numbers
You choose which answer best suits your problem.
Answer:
11.5 tanks of gas
Step-by-step explanation:
23/2
11.5
The positions of the sun, earth and shooting star form a right angled triangle, where distance between earth and sun is 'y', and the angle 'x°' is given
Now, in a right angled triangle using trigonometry, we can determine a side of the triangle is one of the sides and one of the angles is known
Here, if we use cos x = 
we can determine the distance between the shooting star and the sun. This can be done because we know that the base is 'y', the angle is x° and the hypotenuse represents the distance between the sun and the shooting star
Note: cos values for each x are definite.
