Since she has seven key the probability that the first one will open the door is

if it takes three attempts to open the door,the probability is

if the three attempts would not work
then the probability that the fourth attempt will open the door is

hope this helps
The best approximation for the solution to this system of equations is (-2.2,-3)
Option C is correct.
Step-by-step explanation:
Solving the system of equations to get the exact value of x:

Let

Putting value of y from eq(1) into eq(2)



So, Value of x is -2.2
The best approximation for the solution to this system of equations is:
x=-2.2 and y = -3
(-2.2,-3)
Option C is correct.
Keywords: System of equations
Learn more about system of equations at:
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Answer:
I didn't even realize until I had written all of the answers down that they are all <u><em>C.</em></u>
37 = C. <u>15%</u>
38 = C. <u>2
</u>
39 = C. <u>48</u>
Step-by-step explanation:
37: I used process of elimination to figure out which percentage of decrease it was by just multiplying 42 by each percentage until I got 6.3 which is what you need to subtract from 42 to get 35.7, so the answer is C, or 15%.
38: A coefficient is the number that is being multiplied by the variable, which in this case is "x". So whatever answer involves "2x" is the correct answer. Therefore the answer is C, or <u>2
.</u>
39: You have to add the amount of money Henry paid for painting supplies and how much profit he mad to figure out how much money he really made. 400 + 560 = 960 and he charges $20 for each painting so you need to divide 960/20 to get your answer, which is C, or 48.