A motorboat travels 81 miles in 3 hours going upstream. It travels 135 miles going downstream in the same amount of time. What is the rate of the boat in still water and what is the rate of the current?

Answer:

TRUE Elimination will give you an exact answer to a system of equations.

FALSE If substituting the test point produces a false solution, we shade on the opposite side of the line.

The required value of x is 36

Step-by-step explanation :

Let the required number be x.

Three fourth of number = (3/4)x

One third of number = (1/3) x

According to the question ;

3x/4 = x/3 + 15

→ 3x/4-x/3 = 15

→ 9x - 4x / 12 = 15

→ 5x = 15 x 12

⇒ x = 180 / 5

⇒ x = 36

Answer:

a is 44 degree

Step-by-step explanation:

Answer:

The 95% confidence interval for the difference in proportion of registered voters that support this candidate between the northern and southern halves of the state is (0.05, 0.112).

Step-by-step explanation:

Before building the confidence interval, the central limit theorem and subtraction of normal variables is explained.

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]

Subtraction between normal variables:

When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.

Northern half:

1062 out of 2000, so:

[tex]p_N = \frac{1062}{2000} = 0.531[/tex]

[tex]s_N = \sqrt{\frac{0.531*0.469}{2000}} = 0.0112[/tex]

Southern half:

900 out of 2000, so:

[tex]p_S = \frac{900}{2000} = 0.45[/tex]

[tex]s_S = \sqrt{\frac{0.45*0.55}{2000}} = 0.0111[/tex]

Distribution of the difference:

[tex]p = p_N - p_S = 0.531 - 0.45 = 0.081[/tex]

[tex]s = \sqrt{s_N^2 + s_S^2} = \sqrt{0.0112^2 + 0.0111^2} = 0.0158[/tex]

Confidence interval:

The confidence interval is:

[tex]p \pm zs[/tex]

In which

z is the z-score that has a p-value of [tex]1 - \frac{\alpha}{2}[/tex].

95% confidence level

So [tex]\alpha = 0.05[/tex], z is the value of Z that has a p-value of [tex]1 - \frac{0.05}{2} = 0.975[/tex], so [tex]Z = 1.96[/tex].

The lower bound of the interval is:

[tex]p - zs = 0.081 - 1.96*0.0158 = 0.05[/tex]

The upper bound of the interval is:

[tex]p + zs = 0.081 + 1.96*0.0158 = 0.112[/tex]

The 95% confidence interval for the difference in proportion of registered voters that support this candidate between the northern and southern halves of the state is (0.05, 0.112).

Answer:

A =147 cm^2

Step-by-step explanation:

A = pi r^2

The radius is 7 and let pi = 3

A = 3*7^2

A = 3*49

A =147

Answer:

1. velocity

Step-by-step explanation:

that is the answer above

Answer:

6 1/10

Step-by-step explanation:

Convert the mixed numbers into improper fractions (denominator × whole number + numerator / denominator):

9 2/5 = 47/5

3 3/10 = 33/10

Convert improper fractions to have the same denominator:

47/5 × 2/2 = 94/10

Find the difference by subtracting the numerators:

94/10 - 33/10 = 61/10

Convert the answer into a mixed number:

61/10 = 6 1/10

Answer:

Step-by-step explanation:

Answer:

[tex]6(4c + 6d + 3})[/tex]

Step-by-step explanation:

Given

[tex]{24c + 36d + 18}[/tex]

Required

Apply distributive property

We have:

[tex]{24c + 36d + 18}[/tex]

Factor out 6 (to apply distributive property)

[tex]{24c + 36d + 18} = 6(4c + 6d + 3})[/tex]

Hence, the equivalent is:

[tex]6(4c + 6d + 3})[/tex]

Answer:

D. 638 in^2

Step-by-step explanation:

total surface area is just the sum of areas of each side of the cube

opposite sides have the same area

top and bottom = 9*11

sides = 11*9

front and back = 11*11

SA = 2(9*11 + 11*9 + 11*11)

SA = 2(99 + 99 + 121)

SA = 2(319)

SA = 638 in^2

Answer:

Step-by-step explanation:

Value of the car at the end of the first year = £9680

Depreciation = 12 %

Original price = £ x

If we reduce 12% of original price from x, we will get £9680

x - 12% of x  = £ 9680

[tex]x-\frac{12}{100}x=9680\\\\\\\frac{88}{100}x=9680\\\\x=9680*\frac{100}{88}\\\\x = 11000[/tex]

Original price  = £ 11000

Answer:

D

Step-by-step explanation:

m= (y2-y1)/(x2-x1)

m(x2-x1)= y2-y1

y2= m(x2-x1) + y1

Answer:

B. PM = NP

Step-by-step explanation:

Answer:

The variable

Step-by-step explanation:

Answer:

D. ½y(x+z)

Step-by-step explanation:

the area = (x.y)+(½y(z-x))

= xy + ½ (yz -xy)

= xy +½yz -½xy

= ½xy + ½yz

= ½y(x+z)

Answer:

4/5 of the wall

Step-by-step explanation:

In 1/4 of an hour, 1/5 of the wall is painted. That means that

in 4/4 of an hour (which is an hour), 4/5 of the wall is painted.

4/5 is your answer

Step-by-step explanation:

2x-3x=5+10

-x=15

X=-15

2x+1=0.... 1

X-1=0

X=1......2

Substitute the value of x in equation 1

2*1+1=0

2=1

So the value of x is 1 and 2

Answer:

x=-1/2

x=1

x=-15

Step-by-step explanation:

72 - 45 = 27

Samantha took 27 coins. She took 3 dimes, 2 nickels and all but 1 penny, so 7 pennies. This is 12 coins. The rest must be quarters. 27 - 12 = 15 quarters.

15 x 0.25 = 5.25

The value of the quarters that Samantha took is $3.75.

Hope this helps!

Answer:

a,0

Step-by-step explanation:

Look at point (a,b). Point (a,b) has the same x-coordinate as P. And then the y coordinate is 0 because it just sits on the x axis and doesn't go up any. Therefore the answer is P: (a,0).

Answer:

0.002 seconds

Step-by-step explanation:

Wave period = Wavelength/Velocity

Period = 6/3,000

Period = 0.002 seconds

Answer:

4,-10.-4

Step-by-step explanation:

intergers are whole numbers

Answer:

4

-10

-4

Step-by-step explanation:

got it right on edge

Answer:

(675°F − 32) × 5/9 + 273.15 = 630.372K

Hope it's right if not so sorry :)

Answer:

Q1. Volume of the prism

= 75(20)(14) cm3

=21000 cm3

Volume of the cylinder

= π(75^2)(120)cm3

=2120575cm3 (cor. to nearest int.)

The cylindrical bale has a greater volume.

Q3a. Volume of the pyramid

=(1/3)(40)(64)(64)m3

=54613 m3 (cor. to nearest int.)

Q3b. Volume of air per person

=(1/3)(40)(64)(64)(1/5000) m3

=10.9 m3 (cor to 3 sig fig)

Answer:

2lnf .÷f35%vbbcy^hjv6bs8nc

hope it helps you...............

Answer:

the answer is (x+1)(x+2)(2x+1)

Answer:

The expression is not factorable with rational numbers.

x² − 4x + 7

Answer:

2

Step-by-step explanation:

Basically, the period of a sinusoidal graph is the distance between one cycle to another. As can be visually seen, this is 2.

Answer:

2

Step-by-step explanation:

its right on Acellus

Answer: 1 month = 500ml

4 month = 500ml × 4 = 2000ml = 2L

you should use the 2L container

Step-by-step explanation: