About 4.1 seconds. How long was the ball in the air? We are told that t represents time in seconds since the ball was thrown, so it started to be 'in the air' at t = 0 To answer the question, then, we need to know the time when it stopped being in the air. We are told that the ball hit the ground. So that's what happened when it stopped being airborne. We need to relate that event to the mathematics we're working with. What can we say about h , the height of the ball when the ball hits the ground? Answer: The height will be 0 when the ball stops being in the air. Now translate this back to the mathematics: The ball is in the air from t = 0 until the time t when h = 0 . Find the time t that makes h = 0 . That means: solve: − 5 t 2 + 20 t + 2 = 0 We can solve this by solving: 5 t 2 − 20 t − 2 = 0 (Either multiply both sides of the equation by − 1 , or add 5 x 2 − 20 x and − 2 to both sides and then re-write it the other way around) That's a quadratic equation, so try to factor first. But don't spend too much time trying to factor, because not every quadratic is easily factorable and that's OK, because we still have the quadratic formula if we need it. We do need it. t = − ( − 20 ) ± √ ( − 20 ) 2 − 4 ( 5 ) ( − 2 ) 2 ( 5 ) = 20 ± √ 440 10 = 20 ± √ 4 ( 110 ) 10 = 20 ± 2 √ 110 10 = 2 ( 10 ± √ 110 ) 2 ( 5 ) = 10 ± √ 110 5 We can see that 10 < √ 110 < 11 . In fact ( 10 + 1 2 ) 2 = 10 2 + 10 + 1 4 = 110.25 Using 10.25 as an approximation for √ 110 , we get : for the solution t = 10 − √ 110 5 we'll get a negative t . That doesn't make sense. The other solution gives t ≈ 10 + 10.25 5 = 20.5 5 = 4.1 seconds. So the ball was in the air from t = 0 until about t = 4.1 . The elapsed time is the difference, 4.1 seconds.
Answer: Cone
Step-by-step explanation: What solid figure has a circular base and one vertex?
Answer:
a
b
Step-by-step explanation:
From the question we are told that
The probability that an employees suffered lost-time accidents last year is 
The probability that an employees suffered lost-time accident during the current year is
The probability that an employee will suffer lost time during the current year given that the employee suffered lost time last year is
Generally the probability that an employee will experience lost time in both year is mathematically represented as
=> 
=> 
Generally the percentage of employees that will experience lost time in both year is mathematically represented as
=> 
=>
Generally the probability that an employee will experience at least one lost time accident over the two-year period is mathematically represented as
=> 
=> 
Generally the percentage of the employees who will suffer at least one lost-time accident over the two-year period is mathematically represented as
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=>
1) change 65% to a decimal = .65
2) .65 • 60 = 37.2 questions need to be right
3) since she got 42 correct, that is greater than 37.2, so she passed.
OR
1) 42/60 = 0.7
2) 0.7 to a percent = 70%
3) since she got a 70% on the test, she passed.
Answer:
6.087
Step-by-step explanation:
0.000
^ones
^tenths
^hundredths
^thousandths
