The probabilities of knocking down zero, one, and two pins are

and

, respectively. The total probability of knocking down at most two is thus

, or

.
Answer:
B. 18
Step-by-step explanation:
Given:
There are two chord in the circle.
These chords are divided in two segments.
Segments of 1 chord is 21 and 6.
Segments of 2 chord is x and 7.
Now by using Intersecting Chord Theorem which states,
"When two chords intersect each other inside a circle, the products of their segments are equal."
Hence from above theorem we can say that;

Hence the Value of x is 18.
Answer:
If
is divisible by 3, the n is also divisible by 3.
Step-by-step explanation:
We will prove this with the help of contrapositive that is we prove that if n is not divisible by 3, then,
is not divisible by 3.
Let n not be divisible by 3. Then
can be written in the form of fraction
, where x and y are co-prime to each other or in other words the fraction is in lowest form.
Now, squaring

Thus,


It can be clearly seen that the fraction
is in lowest form.
Hence,
is not divisible by 3.
Thus, by contrapositivity if
is divisible by 3, the n is also divisible by 3.
I’m pretty sure a is always and b is sometimes.