Answer:
0.7698
Step-by-step explanation:
If you call your random variable 
, then what you are looking for is
because you want the probability of being <em>between 87 and 123.</em>
We need a table with of the normal distribution. But we can only find the table with 
and 
. Because of that, first we need to <em>normalize </em>our random variable:
(you can always normalize your variable following the same formula!)
now we can do something similar to our limits, to get a better expression:
And we transform our problem to a simpler one:
(see Figure 1)
From our table we can see that 
(this is represented in figure 2).
Remember that the whole area below the curve is exactly 1. So we can conclude that 
(because 0.8849 + 0.1151 = 1). We also know the normal distribution is symmetric, then
.
FINALLY:
Answer:
3/12 or simplified 1/4
Step-by-step explanation:
First make the denominators the same. We can make 12 the common denominator. To make 3/4 have a denominator do the following:
Multiply the numerator and denominator by 3 since 4x3=12. The new number becomes 9/12.
Then subtract:
9/12-6/12=3/12 The numerator subtracts while the denominator stays the same.
We can simplify 3/12 to 1/4
Answer:
15
Step-by-step explanation:
38/2.5=15.2
Round it to 15
B. A smaller percentage of second-lunch students (38%) eat outside.
Write the first ratio as 11/100 and set it equal to 22/n.
since 11 x 2=22 you can multiply 100 x 2 and you'll get 200.
*Check*: 11% of 200=22
