Answer: $19.6
Step-by-step explanation:
Linear function: f(x)=mx+c
, where m= rate of change in f(x) with respect to x.
c = Initial value.
Let c = Initial value of card , m= Charge per minute
x= Number of minutes calling time.
Then, 25.06= 38m+c (i)
21.03=69m+c (ii)
Eliminate (ii) from (i)

Put m in (i) , we get

i.e. f(x)=-0.13x+30
if x=80 then
f(80)= -0.13(80)+30
=-10.4+30
=19.6
Hence, the remaining credit after 80 minutes of calls = $19.6
(X)(3.25)(4)= 110.5
4
(x)(3.25)= 27.625
3.25
x = 8.5
(8.5)(3.25)(4)= 110.5
Answer: b. 30%
Step-by-step explanation:
- A measure of relative variability is known as coefficient of variation. It is the ratio of the standard deviation to the mean.
i.e. 
Given: mean = 
Variance = 

Now, 
in percent , 
Hence, correct option is b. 30%.
Answer: Ix - 950°C I ≤ 250°.
Step-by-step explanation:
Ok, the limits are:
700°C to 1200°C.
The first step is to find the mean these numbers:
M = (700°C + 1200°C)/2 = 950°C
Now let's find the distance between the mean and the limits (which is equal to half the difference between our numbers)
D = (1200°C - 700°C)/2 = 250°C.
Now we can write our relation as:
Ix - MI ≤ D
Ix - 950°C I ≤ 250°.
if x = 1200°C.
I1200°C - 950°CI = 250°C ≤ 250°C ---- true.
if x = 700°C
I700°C - 950°CI = I-250°CI = 250°C ≤ 250°C ---- true
Answer:
-0.875
Step-by-step explanation: