Answer:
- The system of equations is x + y = 85 and 7/20x+2/5y=31
- To eliminate the x-variable from the equations, you can multiply the equation with the fractions by 20 and multiply the other equation by -7.
- B-She used 60 minutes for calling and 25 minutes for data.
Step-by-step explanation:
It is always a good idea to start by defining variables in such a problem. Here, we can let x represent the number of calling minutes, and y represent the number of data minutes. The the total number of minutes used is ...
x + y = 85
The total of charges is the sum of the products of charge per minute and minutes used:
7/20x + 2/5y = 31.00
We can eliminate the x-variable in these equations by multiplying the first by -7 and the second by 20, then adding the result.
-7(x +y) +20(7/20x +2/5y) = -7(85) +20(31)
-7x -7y +7x +8y = -595 +620 . . . . eliminate parentheses
y = 25 . . . . . . . . simplify
Then the value of x is
x = 85 -y = 85 -25
x = 60
Answer:
a = -5
Step-by-step explanation:
(5 - 3)/(5 - a)
2/(5 - a)
perpendicular of 2/(5 - a) = -(5 - a)/2
(a - 0)/(1 - 0) = -(5 - a)/2
a/1 = -(5 - a)/2
2a = -5 + a
a = -5
Answer:
The value is 
Step-by-step explanation:
From the question we are told that
The capacity of the metal tank is 
The duration usage is 
The cost of 2000-gallon tank 15 years ago is 
The capacity of the second tank considered is 
The power sizing exponent is 
The initial construction cost index is 
The new construction after 15 years cost index is 
Equation for the power sizing exponent is mathematically represented as
![\frac{P_n}{P} = [\frac{C_1}{C} ]^{e}](https://tex.z-dn.net/?f=%5Cfrac%7BP_n%7D%7BP%7D%20%3D%20%5B%5Cfrac%7BC_1%7D%7BC%7D%20%5D%5E%7Be%7D)
=> Here 
is the cost of 5,000-gallon tank as at 15 years ago
So
![P_n = [\frac{5000}{2000} ] ^{0.57} * 100000](https://tex.z-dn.net/?f=P_n%20%20%3D%20%20%5B%5Cfrac%7B5000%7D%7B2000%7D%20%5D%20%5E%7B0.57%7D%20%2A%20100000)
Equation for the cost index exponent is mathematically represented as
Here
is the cost of 5,000-gallon tank today
So
=> 
=>
Expected value is $20.20
Step-by-step explanation:
Here, we want to calculate the expected value
What we have to do here is to multiply the probability by the payout value; after which we add all values
Thus, we have the payout value as;
1(0.12) + 4(0.2) +6(0.38) + 8(0.2) + 10(0.1)
= 0.12 + 0.8 + 2.28 + 1.6 + 1
