Answer:
It will take nine years and four months for the refrigerator to pay for itself.
Step-by-step explanation:
The new refrigerator which costs $1200, saves the family 22% annually in energy cost.
Since the old refrigerator costs $580 to run, we want to determine how many years it will take for 22% of $580 per year to make $1200.
22% of $580
= 580 × 0.22
= 127.6
That is, it saved then $127.6 per year.
Now,
$1200/127.6
≈ 9.4
Which means, it will take 9 years and 4 months for the refrigerator to pay for itself.
Answer:area is 150 cm
Step-by-step explanation:
Its because the power of zero is undefined
3. 9a+9b
4. 3n+21
5. 30+2q
6. ab+8a
Answer:
The error E = ± 4.04 %
Step-by-step explanation:
Solution:-
- The sample data is used to estimate the population proportion ( p ).
- The success p^ = success percentage = 40 %
- The confidence interval CI = 98%
- The sample size n = 800
- The margin of error E:
- The margin of error "E" for estimation of population proportion ( p ) is given by:

Where, Z-critical value is defined by the significance level:
P ( Z < Z-critical ) = α / 2
Where, α : Significance level
α = 1 - CI
P ( Z < Z-critical ) = (1 - 0.98) / 2
P ( Z < Z-critical ) = 0.01
Z-critical = 2.33
- The error E of estimation is:

- The error E = ± 4.04 %