Answer:
a = 1/2 (1 ±sqrt(47))
Step-by-step explanation:
a^2-a+12=0
We will complete the square
Subtract 12 from each side
a^2-a+12-12=0-12
a^2-a=-12
The coefficient of a = -1
-Divide by 2 and then square it
(-1/2) ^2 = 1/4
Add it to each side
a^2 -a +1/4=-12 +1/4
(a-1/2)^2 = -11 3/4
(a-1/2)^2= -47/4
Take the square root of each side
sqrt((a-1/2)^2) =sqrt(-47/4)
a-1/2 = ±i sqrt(1/4) sqrt(47)
a-1/2= ±i/2 sqrt(47)
Add 1/2 to each side
a-1/2+1/2 = 1/2± i/2 sqrt(47)
a = 1/2± i/2 sqrt(47)
a = 1/2 (1 ±sqrt(47))
Answer:
a) 658008 samples
b) 274050 samples
c) 515502 samples
Step-by-step explanation:
a) How many ways sample of 5 each can be selected from 40 is just a combination problem since the order of selection isn't important.
So, the number of samples = ⁴⁰C₅ = 658008 samples
b) How many samples of 5 contain exactly one nonconforming chip?
There are 10 nonconforming chips in the batch, and 1 nonconforming chip for the sample of 5 be picked from ten in the following number of ways
¹⁰C₁ = 10 ways
then the remaining 4 conforming chips in a sample of 5 can be picked from the remaining 30 total conforming chips in the following number of ways
³⁰C₄ = 27405 ways
So, total number of samples containing exactly 1 nonconforming chip in a sample of 5 = 10 × 27405 = 274050 samples
c) How many samples of 5 contain at least one nonconforming chip?
The number of samples of 5 that contain at least one nonconforming chip = (Total number of samples) - (Number of samples with no nonconforming chip in them)
Number of samples with no nonconforming chip in them = ³⁰C₅ = 142506 samples
Total number of samples = 658008
The number of samples of 5 that contain at least one nonconforming chip = 658008 - 142506 = 515502 samples
1. Find the total number of class members
9 + 11 = 20
2. Find 9 as a percentage of 20
9 / 20 = 0.45
0.45 x 100 = 45%
<u>45% of the class are girls.</u>
I have no clue I don’t understand this
Answer:
A
Step-by-step explanation:
44 - 15 =29
