The number of students would not change between before the test and after the test. 3+8 and 4+7 both = 11 so finding out how many students would equal one ratio can then be used to find how many equal 3 and 8.
If 92 students are equal to 4 in the ratio, then 1 in the ratio is worth 23 students. This is important as then when you times 23 by 7 you find out how many students there are in the regular maths class, 161 students. Plussing these two together gives you a total of 253 students.
Using this 253 you can divide it by 11 to find out how much 1 number would be in the ratio, it equals 23. Using this you can then times 23 by both 3 and 8 to find the original class sizes, 3x23 = 69, and 23x8 = 184.
Making the origional class size of the advaced class 69 studnets, and the regular maths class size 184.
Answer:
Step-by-step explanation:
Previous concepts
The expected value of a random variable X is the n-th moment about zero of a probability density function f(x) if X is continuous, or the weighted average for a discrete probability distribution, if X is discrete.
The variance of a random variable X represent the spread of the possible values of the variable. The variance of X is written as Var(X).
Solution to the problem
Since the warranty on a machine specifies that it will be replaced at failure or age 4 and the distribution for X is defined between 0 and 5 then if we define the random variable Y ="the age of the machine at the time of replacement" we know that the values for Y needs to be between 0 and 4 or between 4 and and we can define the following density function:
for other case
Now we can apply the definition of expected value and we have this:
And for the second moment we have:
And the variance would be given by:
3+1=4, 4+2=6, 6+3=9, 9+4=13, 13+5=18, 18+6=24, 24+7=31. Your answer is 31. Each time , the number you add by is increased by 1
Answer:
c
Step-by-step explanation:
common sense
100/12
100/12 = 25/3 = 8 1/3 ft/min