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ASHA 777 [7]
2 years ago
13

One month, a homeowner used 150 units of gas and 520 units of electric for a total cost of $84.20. The next month, 210 units of

gas and 405 units of electric were used for a total cost of $82.35. Find the cost per unit of gas and electric using substitution.
Mathematics
1 answer:
Savatey [412]2 years ago
4 0

Answer:

Let g represent the cost of gas and e represent the cost of electricity.

150g + 520e = 84.20  ⇒  7(150g + 520e = 84.20)   ⇒  1050g + 3640e = 576.80

210g + 405e = 82.35  ⇒ -5(210g + 405e = 82.35)  ⇒  -1050g - 2025e = -411.75

                                                                                                       1615e = 165.05

                                                                                                               e = 0.10

150g + 520(0.10) = 84.20

150g + 52 = 84.20

140g = 32.20

    g = 0.23

Answer: gas = $0.23, electricity = $0.10

Step-by-step explanation:

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The length of the day in Lagos, Nigeria (in minutes), ttt days since the beginning of the year can be estimated by this formula:
Ronch [10]

Answer:

The longest day of the year is day 172  

Step-by-step explanation:

Since the length of day is L(t)=727+22sin[2π(t−80.75)/365], the maximum length of day is obtained when sin[2π(t−80.75)/365] is at its maximum value which is 1. So. sin[2π(t−80.75)/365] = 1

We now solve this to find the day at which this maximum value occurs.

sin[2π(t−80.75)/365] = 1

[2π(t−80.75)/365] = sin⁻¹(1)

[2π(t−80.75)/365] = π/2

dividing both sides by 2π/365, we have

[2π(t−80.75)/365] ÷ 2π/365 = π/2 ÷ 2π/365

t−80.75 = 365/4

t−80.75 = 91.25

t = 91.25 + 80.75

t = 172

The longest day of the year is day 172

6 0
2 years ago
1. The speed at which an automated assembly line produces a product follows a normal distribution with mean production time of 3
strojnjashka [21]

Answer: Probability = 0.2

Step-by-step explanation:

Given data:

Mean production time = 32.20 seconds

Standard deviation = 1,05seconds

probability that a full production run will take less than 32 seconds on average to produce

= P(Xbar<32)

= P(Z<-0.8518)

= 0.2

8 0
2 years ago
A contaminant is leaking into a lake at a rate of R(t) = 1400e0.06t gallons/h. Enzymes have been added to the lake that neutrali
ruslelena [56]

Answer:

Step-by-step explanation:

Rate of leakage, R(t) = 1400 e^0.06t gallons/h

fraction remains , S(t) = e^(-0.32t)

initial contaminant = 1000 gallon

gallons contaminant present after t hour is S(t) R(t)

G(t) = S(t) R(t)

G(t) = 1400 e^{0.06t}\times e^{-0.32t}

G(t) = 1400 e^{- 0.26t}

Put t = 18 hours

G(t) = 1400 e^{- 0.26\times 18}

Taking log on both the sides

ln G = ln 1400 - 0.26 x 18

ln G = 7.244 - 4.68

ln G = 2.564

G = 13 gallons

5 0
2 years ago
A botanist collected one leaf at random from each of 10 randomly selected mature maple trees of the same species. The mean and t
Zarrin [17]

Answer:

One sample t-test for population mean would be the most appropriate method.

Step-by-step explanation:

Following is the data which botanist collected and can use:

  • Sample mean
  • Sample Standard Deviation
  • Sample size (Which is 10)
  • Distribution is normal

We have to find the best approach to construct the confidence interval for one-sample population mean. Two tests are used for constructing the confidence interval for one-sample population mean. These are:

  • One-sample z test for population mean
  • One-sample t test for population mean

One sample z test is used when the distribution is normal and the population standard deviation is known to us. One sample t test is used when the distribution is normal, population standard deviation is unknown and sample standard deviation is known.

Considering the data botanist collected, One-sample t test would be the most appropriate method as we have all the required data for this test. Using any other test will result in flawed intervals and hence flawed conclusions.

Therefore, One-sample t-test for population mean would be the most appropriate method.

8 0
2 years ago
The graphs below have the same shape. What is the equation of the red graph?
Alex787 [66]

Answer:

c

Step-by-step explanation:

since the axis of symmetry is 0, and the y intercept is 2, the answer should be c

4 0
2 years ago
Read 2 more answers
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