The police department uses a formula to determine the
1 answer:
9514 1404 393
Answer:
78.71 mph
Step-by-step explanation:
You're looking for the solution to ...
d = 88
0.0015r^2 +r = 88
0.0015r^2 +r -88 = 0
Using the quadratic formula*, we find ...
r = (-1 +√(1² -4(0.0015)(-88)))/(2×0.0015)
r = (-1 +√1.528)/0.003 = 0.236123/0.003 = 78.7077
The speed of the car was about 78.71 mph.
_____
* The quadratic formula will also give a negative answer of about -745 mph, which is not relevant to the situation.
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Answer:
As exact answers:
and
As decimal answers:
x = -6.2749172 ≈-6.3
x = 1.27491722 ≈ 1.3
Step-by-step explanation:
For quadratic equations, you can use the quadratic formula. Rearrange the equation to standard from, which is ax² + bx + c = 0.
x² = –5x + 8
x² + 5x - 8 = 0
State the values for "a", "b" and "c",
a = 1; b = 5; c = -8
(Ignore the Â, it's a formatting error)
Simplify
Two negatives make a positive
Split the equation at the ± for plus and minus:
= 1.27491722 ≈ 1.3
= -6.2749172 ≈ -6.3
Therefore the solutions are 1.3 and -6.3.
Answer:
Therefore the answer is 20.
Step-by-step explanation:
We know that
class interval = range / number of classes
But here number of classes is not given , so we use the formula
class interval = range / ( 1+ 3.322 log N)
where , range =maximum - minimum = 220-100 = 120
N= number of observations = 50
class interval = 120 / ( 1+ 3.322 * log 50) = 18.06
Rounding up to a convinient number
Thus , class intervai = 20
Therefore the answer is 20.
