30×30=900
900/112.5=8 cameras to cover
112.5×4=450
900-450=450 ft left uncovered
8 seconds
The hardest part of this is setting up the equation -- the calculations are pretty easy.
You're told that the time (needed to go from 0 to 100 MPH) is inversely proportional to the horsepower: what this means is that as horsepower gets larger, time gets smaller. This makes sense since the more horsepower you have, the less time it will take you to get to 100 MPH
You can think of this as:
200 HP = 10 seconds
250 HP = x seconds
You set the equation up as:
250 HP / 200 HP = 10 sec / x sec
Now, just cross multiply and solve:
250 / 200 = 10 / x
250x = (200 x 10)
250x = 2000
x = 2000 / 250
x = 8
So, as you increase the horsepower from 200 to 250, the time decreases from 10 seconds to 8 seconds.
Hope this helps!
Good luck.
Answer:
Step-by-step explanation:
last one
Answer:
The mean for the second week is $2 less than the first and in percentage it is 22% less.
Step-by-step explanation:
The mean is given by the sum of all individual values divided by the number of values. For the first week the sum is:
sum1 = 6.5 + 8 + 7.25 + 13.5 + 9.75
sum1 = 45
Since she spent 10 less in the second week the sum is:
sum2 = sum1 - 10 = 45 - 10 = 35
The mean for each week is:
mean1 = sum1/5 = 45/5 = 9
mean2 = sum2/5 = 35/5 = 7
difference = mean1 - mean2 = 9-7 = 2
difference(%) = [2/9]*100 = 0.22*100 = 22%
The mean for the second week is $2 less than the first and in percentage it is 22% less.