Answer:
Step-by-step explanation:
Given that the time to complete a standardized exam is approximately normal with a mean of 70 minutes and a standard deviation of 10 minutes.
P(completing exam before 1 hour)
= P(less than an hour) = P(X<60)
=P(Z<
)
=0.5-0.34=0.16
i.e. 16% of students completed the standardized exam.
22.5/(x-6) + 22.5/(x+6) = 9
multiply by x-6
=> (x-6)22.5/(x-6) + (x-6)22.5/(x+6) = 9(x-6)
=> 22.5 + (x-6)22.5/(x+6) = 9(x-6)
multiply by x+6
=> (x+6)22.5 + (x+6)(x-6)22.5/(x+6) = 9(x-6)(x+6)
=> (x+6)22.5 + (x-6)22.5 = 9(x-6)(x+6)
distribute
=> 22.5x+6(22.5) + 22.5x - 6(22.5) = 9(x^2 - 36)
=> 45x = 9x^2 - 9(36)
=> 0 = 9x^2 - 45x - 9(36)
divide by 9
=> 0 = x^2 - 5x - 36
=> 0 = x^2 - 5x - 36
=> 0 = (x - 9)(x + 4)
x=9 and -4
Answer:
3
Step-by-step explanation:
43.0810
Since the hundred thousandths is a 1 which is less than a 5, you have to round down.
Answer: Maggie is 29 years old
Step-by-step explanation:
12*3=36
36-7=29
29 + 12 = 41