Answer:
Correct choice is B
Step-by-step explanation:
Let x% be your final test score, then the average of all test scores is

Since you must have an average between 80% and 89%, then

X is measured in percent, then the greatest value of x can be 100%. You get that

solve by elimination
we can see that we can eliminate y from both equations by mulitpying the 2nd equation by 2 and adding them
x+6y=1
<u>4x-6y=64 +</u>
5x+0y=65
5x=65
divide both sides by 5
x=13
subsitute back
x+6y=1
13+6y=1
minus 13 both sides
6y=-12
divide by 6 both sides
y=-2
solution is x=13 and y=-2 or (13,-2) is the solution
Its i think going to be 290 seconds
Answer:
The probability of flipping a coin 10 times and it landing on heads exactly seven times is about 0.1172 or 11.72%.
Step-by-step explanation:
We can use basic binomial distribution, which is given by the formula:

Where <em>n</em> represent the number of trials, <em>x</em> represent the number of successes desired, <em>p</em> represent the chance of success, and <em>q</em> represent the chance of failure.
Since we are flipping a coin 10 times, we are conducting 10 trials. So, <em>n</em> = 10.
We want to probability that it lands on heads exactly 7 out of 10 times. So, the number of desired successes <em>x</em> is 7.
The probability of success <em>p</em> is 1/2.
And the probability of failure <em>q</em> is also 1/2.
Substituting:

The probability of flipping a coin 10 times and it landing on heads exactly seven times is about 0.1172 or 11.72%.
Encuentra el valor de x. Redondea tu respuesta a la décima más cercana.