Answer:
24
Step-by-step explanation:
75% of x = 18
75/100 * x = 18 (x = total number of students)
solving
x = 24
total number of students = 24
Checking:
75/100 * 24 = 18
Answer:
width = 2 units
Step-by-step explanation:
If the length of a rectangle is (x) units, then that means that the width of a rectangle is x - 4 units.
the area of a rectangle is length * width
so just substitute the values that we have now.
x (length) * (x-4) width = 12 (area of rectangle)
so that gives us
x^2 - 4x =12
subtract 12 from both sides
x^2 - 4x - 12 =0
now factor this equation
x^2 + 2x - 6x -12 = 0
x(x+2) - 6(x+2) = 0
(x-6)(x+2) = 0
x = 6, or x = -2 REMEMBER THAT VALUE OF x = LENGTH, IT CANNOT BE NEGATIVE AS YOU CANT HAVE NEGATIVE VALUE OF A SIDE
length = 6, and width = 6 -4 = 2
Answer:
17.5%
Step-by-step explanation:
First of all, see this situation as a cumulative binomial distribution. You have isolated trials with a probability of success. This makes it binomial. The wording of the question "what is the probability of at least half..." makes this cumulative.
There are a few ways to calculate this, and I'm not quite sure which way you're familiar with. I'll show the cumbersome way and use wolfram to make the calculation.
First, I'll calculate the probability for 15 success, given 30 trials.
30c15*0.4^15*0.6^15
Since the question asks for the probability of at least 15 success, I'll have to make a calculation for the probability of 16 successes, then 17, and so on. Then I'll have to add all the probabilities together. So, I'll use wolfram for that (see attached)
The best answer would be Blister