The toy rocket hits the ground when h(t) = 0.
So, h(t) = 0 = -9t^2 + 81.
Solving the equation,
-9t^2 = -81
Dividing by -9
t^2 = 9
Taking the square root.
t = 3
The answer is 3 seconds.
Answer: B
Step-by-step explanation:
No, A and B are not independent events
Step-by-step explanation:
Let us study the meaning independent probability
- Two events are independent if the result of the second event is not affected by the result of the first event
- If A and B are independent events, the probability of both events is the product of the probabilities of the both events P (A and B) = P(A) · P(B)
∵ P(A) = 
∵ P(B) = 
∴ P(A) . P(B) =
× 
∴ P(A) . P(B) = 
∴ P(A) . P(B) = 
∵ P(A and B) = 
∵ P(A) . P(B) = 
- The two answers are not equal
∴ P (A and B) ≠ P(A) · P(B)
- In independent events P (A and B) = P(A) · P(B)
∴ A and B are not independent events
No, A and B are not independent events
Learn more:
You can learn more about probability in brainly.com/question/13053309
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Recall your d = rt, distance = rate * time
one car is going at 55kph, at say hmmm "t" time
the second car zooms by at 75kph, an hour later, thus " t + 1 "
notice, overtaking the 1st car, simply means, the second car comes from behind approaches the first car from behind and "gets there", at that very second, both cars have travelled a distance, say "d"
if the first car travelled "d" kilometers
for the second car to "get there" has to had travelled "d" distance as well

solve for "t"
Answer:A)0.75
Step-by-step explanation:
Given
There are four options to a question
out of which one is correct with 4 points
one is wrong but carries 1 point
Other two are wrong with a negative Point
Probability of selecting an option is 
Expected score
Expected score=1+0.25-0.5
Expected score=0.75