The formula for Average speed = 
The car travels 80 km in 1 hour.
Then the car travels 90 km in 2 hours.
And finally the car travels 76 km in 1 hour
So the total distance covered by the car = 80 + 90 + 76 = 246 km
The total time taken to cover this distance = 1 + 2 + 1 = 4 hours.
So average speed = 
The average speed of the car is 61.5 km / h
Answer: Choice D
(a-e)/f
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Explanation:
Points D and B are at locations (e,f) and (a,0) respectively.
Find the slope of line DB to get
m = (y2-y1)/(x2-x1)
m = (0-f)/(a-e)
m = -f/(a-e)
This is the slope of line DB. We want the perpendicular slope to this line. So we'll flip the fraction to get -(a-e)/f and then flip the sign from negative to positive. That leads to the final answer (a-e)/f.
Another example would be an original slope of -2/5 has a perpendicular slope of 5/2. Notice how the two slopes -2/5 and 5/2 multiply to -1. This is true of any pair of perpendicular lines where neither line is vertical.
Answer:
f(n)= 5 · 4
Step-by-step explanation:
You use the explicit formula for geometric sequence. The five is the firat term and is placed correctly. The 4 is the rate of change, because if you multiply 5 by 4 you get 20 and so on.
Answer:
A (50)
Step-by-step explanation:
Mean is the total numbers added up divided by the # of numbers.
There are 6 numbers.
51 + 60 + 80 + 32 + 47 + 30 = 300
300/6 = 50
Therefore, the answer is A.
