For a geometric sequence with common ratio

, we have

that is, the

-th term in the sequence is the product of the previous term and the common ratio

. So

Then the sum of the first 7 terms is


Notice that

so we can subtract this modified sum from

to get

We're told that

and

, so the sum of the first 7 terms is
Answer:
19.75%
Step-by-step explanation:
Since we are trying to find the probability for a sequence of events then we need to multiply the probability of each event happening separately from each other. Since the probability of it raining on a single day is 2/3 we need to multiply this value with itself 4 times (one for each day).
2/3 * 2/3 * 2/3 * 2/3 = 16/81 or 0.1975 or 19.75%
Therefore the probability would be 16/81 or 0.1975 or 19.75%
Given:
The equation of ellipse is

To find:
The length of the minor axis.
Solution:
The standard form of an ellipse is
...(i)
where, (h,k) is center, if a>b, then 2a is length of major axis and 2b is length of minor axis.
We have,
...(ii)
On comparing (i) and (ii), we get

Taking square root on both sides.

Consider only positive value of b because length cannot be negative.

Now,
Length of minor axis = 
= 
= 
So, the length of minor axis is 8 units.
Therefore, the correct option is B.
9514 1404 393
Answer:
8 people
Step-by-step explanation:
If 20 of 140 people play tennis, then in a group of 504 people, we expect ...
(20/140) × 504 = 72 . . . . tennis players
If 1 of 9 tennis players has a coach, then in a group of 72 tennis players, we expect ...
(1/9) × 72 = 8 . . . . have a coach
We expect 8 of the 504 people have a tennis coach. We made this prediction by applying the given rates to the larger group.
Y + 4x = 8
y = 8 - 4x
substitute 8 - 4x for y in the other equation.
5x + 2(8 - 4x) = 13
5x + 16 - 8x = 13
-3x = -3
x = 1
y = 8 - 4(1) = 4