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2 years ago

How can i get better at maths

Mathematics

1 answer:

ivann1987 [24]2 years ago

8 0

by consentration at class and think maths is easy solve ur question and see u willl have what u need

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Salaries of 49 college graduates who took a statistics course in college have a mean, x overbar, of $ 65 comma 300. Assuming a

Molodets [167]

Answer: $60,540< \mu$

Step-by-step explanation:

The confidence interval for population mean is given by :-

$\overline{x}-z^*\dfrac{\sigma}{\sqrt{n}}< \mu$

, where $\sigma$ = Population standard deviation.

n= sample size

$\overline{x}$ = Sample mean

z* = Critical z-value .

Given : $\sigma=\$17,000$

n= 49

$\overline{x}= \$65,300$

Two-tailed critical value for 95% confidence interval = $z^*=1.960$

Then, the 95% confidence interval would be :-

$65,300-(1.96)\dfrac{17000}{\sqrt{49}}< \mu$

$=65,300-(1.96)\dfrac{17000}{7}< \mu$

$=65,300-4760< \mu$

$=60,540< \mu$

Hence, the 95% confidence interval for estimating the population mean $(\mu)$ :

$60,540< \mu$

7 0

2 years ago

two pumps of different sizes, working together, can empty a fuel tank in 3 hours. the larger pump can empty the tank in 4 hours

bonufazy [111]

Suppose the larger pump alone can empty the tank in L hours, and the smaller pump can finish the job in S hours, then each hour the large pump empties 1/L portion of the tank, and the small pump empties 1/S per hour
Working together for three hours, they empty the whole tank, which is 100% of it, so 3/L+3/S=100%=1
Larger pump can empty the tank in 4 hours less than the smaller one, so L=S-4
replace L: 3/(S-4)+3/S=1
Make the denominator the same to solve for:
3S/[S(S-4)] +3(S-4)/[S(S-4)]=1
(3S+3S-12)/[S(S-4)]=1
(3S+3S-12)=[S(S-4)]
S^2-10s+12=0
use the quadratic formula to solve for S
S is about 8.6
The answer is not whole hour.

8 0

2 years ago

Read 2 more answers

3x+5=5x-3

madam [21]

answer= d Step-by-step explanation:

6 0

1 year ago

Write the word sentence as an equation. Then solve the equation 12. Your mother asked you to turn the oven down to 325f. This is

Juliette [100K]

Answer: Equation : t - 75 = 325 , Solution: t=400, 400 degree F

t= original temperature