To solve this problem, we use the formula:
z = (x – u) / s
where z is the z score value which can be obtained from
the tables, x is the sample value, u is the mean = 6.3 min, and s is the std
dev = 2.2 min
at P value = 0.90, the z = 1.28, finding for x:
x = z s + u
x = 1.28 * 2.2 + 6.3
x = 9.116
at P value = 1.0, the z = 3.49, finding for x:
x = z s + u
x = 3.49 * 2.2 + 6.3
x = 13.978 ~ 14
Therefore the longest 10% calls last about 9.1 minutes to
14 minutes
Answer:
1/4
Step-by-step explanation:
The value of b^2-4ac is known as the discriminant of a quadratic function, and can tell you how many roots exist of this function depending on what it is equal to.
Start by moving the -1 to the other side, as we need this function to equal zero.
2x^2 + 3x + 1 = 0
This is now the standard form ax^2 + bx + c = 0. Plug each value that corresponds into the discriminant equation.
b^2-4ac
(3)^2 - 4(2)(1)
9 - 8
1
The value of the discriminant is 1, meaning that two real roots exist for the function described.
P(x) = 4x + 1550 <== ur function
selling only 50 copies...
P(50) = 4(50) + 1550
P(50) = 200 + 1550
P(50) = 1750....so the printing cost for 50 copies is 1750
1750 = 50x....x = cost of each book
1750/50 = x
35 = x.......u would have to sell each book for $ 35 <===
