Answer:
C. The 6th term is positive/negative 80
Step-by-step explanation:
Given
Geometric Progression


Required

To get the 6th term of the progression, first we need to solve for the first term and the common ratio of the progression;
To solve the common ratio;
Divide the 7th term by the 5th term; This gives

Divide the numerator and the denominator of the fraction by 40
----- equation 1
Recall that the formula of a GP is

Where n is the nth term
So,


Substitute the above expression in equation 1
becomes


Square root both sides

r = ±
Next, is to solve for the first term;
Using 
By substituting 160 for T5 and ±
for r;
We get


Multiply through by 16



Now, we can easily solve for the 6th term
Recall that the formula of a GP is

Here, n = 6;



r = ±
So,
or 
or 
or 
±80
Hence, the 6th term is positive/negative 80
The easiest way is if it doesn't need to be simplified. Multiply -2.105 by

. You get the fraction

. While this is technically the answer, you can simplify this down to

. Because 421 is a prime number, this can not be simplified any further. Therefore, the solution is

.

.
Answer:
Step-by-step explanation:
Rate X Time = distance
Therefore:
r (rate) X 5 (hours) = 600 (distance)
r = 600/5
r = 120 miles per hour
The rate of speed of the jet is 120 mph.
Then, to find out the distance flown in 13 hours:
120 (rate) X 13 (time) = d (distance)
120 X 13 = d
1560 = d
The distance flown in 13 hours is 1560 miles.
3 / 5 = (x+1) / (y-2)
↓
↓ multiply by 5 / 3
↓
1 = 5 * (x+1) / 3 * (y-2)
↓
↓ move and simplify
↓
5x + 5 = 3y - 6
↓
↓ minus 5
↓
5x = 3y - 11
↓
↓ divide by 5
↓
Answer : x = (3y - 11) / 5
3x - 2 = 7
3x = 7 + 2
3x = 9 (divide both sides by 3 to get x)
3x/3 = 9/3
x = 3