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3 years ago

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A man invests a certain amount of money at 2% interest and $800 more than that amount in another account at 4% interest. At the

end of one year he earned $112 in interest. How much money was invested in each account? Which of the following equations could be used to solve the problem? 0.02x + 0.04(800) = 112 0.02x + 0.04(x + 800) = 112 0.04x + 0.02(x + 800) = 112

2 answers:

Alex777 [14]3 years ago

6 0

112 dallors interest beca0.02x + 0.04(800) = 112 0.02x + 0.04(x + 800) = 112 0.04x + 0.02(x + 800) = 112 use

GaryK [48]3 years ago

5 0

Answer:

0.02x + 0.04(800) = 112

Step-by-step explanation:

Let the unknown amount be x

The amount is invested at 2 % interest so the intrest will be $ 0.02x

However, another amount, this time $ 800 is invested at 4 % interest. This gives:

0.04 (800)

The total amount at the end of the year will be = $ 112

Therefore, the sum of the two interests will be $\\$ 0.02x+ 0.04($800) = $ 112.00$

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Suppose a 90% confidence interval for the mean salary of college graduates in a town in Mississippi is given by [$38,737, $50,46

JulsSmile [24]

Answer:

a. The point estimate was of $44,600.

b. The sample size was of 16.

Step-by-step explanation:

Confidence interval concepts:

A confidence interval has two bounds, a lower bound and an upper bound.

A confidence interval is symmetric, which means that the point estimate used is the mid point between these two bounds, that is, the mean of the two bounds.

The margin of error is the difference between the two bounds, divided by 2.

a. What is the point estimate of the mean salary for all college graduates in this town?

Mean of the bounds, so:

(38737+50463)/2 = 44600.

The point estimate was of $44,600.

b. Determine the sample size used for the analysis.

First we need to find the margin of error, so:

$M = \frac{50463-38737}{2} = 5863$

Relating the margin of error with the sample size:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1 - 0.9}{2} = 0.05$

Now, we have to find z in the Z-table as such z has a p-value of $1 - \alpha$ .

That is z with a pvalue of $1 - 0.05 = 0.95$ , so Z = 1.64.

Now, find the margin of error M as such

$M = z\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

For this problem, we have that $\sigma = 14300, M = 5863$ . So

$M = z\frac{\sigma}{\sqrt{n}}$

$5863 = 1.645\frac{14300}{\sqrt{n}}$

$5863\sqrt{n} = 1.645*14300$

$\sqrt{n} = \frac{1.645*14300}{5863}$

$(\sqrt{n})^2 = (\frac{1.645*14300}{5863})^2$

$n = 16$

The sample size was of 16.

7 0

3 years ago

In the circle below, DB = 22 cm, and m<DBC = 60°. Find BC. Ignore my handwriting.

Karo-lina-s [1.5K]

Answer:

$BC=11\ cm$

Step-by-step explanation:

step 1

Find the measure of the arc DC

we know that

The inscribed angle measures half of the arc comprising

$m\angle DBC=\frac{1}{2}[arc\ DC]$

substitute the values

$60\°=\frac{1}{2}[arc\ DC]$

$120\°=arc\ DC$

$arc\ DC=120\°$

step 2

Find the measure of arc BC

we know that

$arc\ DC+arc\ BC=180\°$ ----> because the diameter BD divide the circle into two equal parts

$120\°+arc\ BC=180\°$

$arc\ BC=180\°-120\°=60\°$

step 3

Find the measure of angle BDC

we know that

The inscribed angle measures half of the arc comprising

$m\angle BDC=\frac{1}{2}[arc\ BC]$

substitute the values

$m\angle BDC=\frac{1}{2}[60\°]$

$m\angle BDC=30\°$

therefore

The triangle DBC is a right triangle ---> 60°-30°-90°

step 4

Find the measure of BC

we know that

In the right triangle DBC

$sin(\angle BDC)=BC/BD$

$BC=(BD)sin(\angle BDC)$

substitute the values

$BC=(22)sin(30\°)=11\ cm$

6 0

3 years ago

Can anyone please help!!!

quester [9]

Answer:

Question 9

(a) The distance, Jalaj walks in one day is 4.4 km

(b) The amount Jalaj raises after walking for 22 km at the end of the 5 days is $8

Question 10

(b) The difference between the largest and smallest areas is 2,400 m²

Step-by-step explanation:

Question 9

(a) The distance Jalaj walks in 5 days = 22 km

Whereby Jalaj walks equal distance every day, we have;

The distance, Jalaj walks in one day = 22 km/5 days = 4.4 km/day

The distance, Jalaj walks in one day = 4.4 km

(b) The amount he raises for every kilometer he walks = $1.60

The amount he raises after walking for 22 km at the end of the 5 days = 5 × $1.60 = $8

Question 10

(b) The given side length of the square = 120 meters to the nearest 10 meters

Therefore;

The maximum dimension for the side length of the square = 120 + 10/2 = 125

The largest possible area of the square, $A_l$ = 125 m × 125 m = 15,625 m²

The minimum dimension for the side length of the square = 120 m - 10 m/2 = 115 m

The smallest possible area of the square, $A_s$ = 115 m × 115 m = 13,225 m².

The difference between the largest and smallest areas, $A_l$ - $A_s$ = 15,625 - 13,225 = 2,400 m².

8 0

2 years ago

...........................

cupoosta [38]

Answer:

3/5 or 0.6

Step-by-step explanation:

Here, given the value of tan theta , we want to find the value of sine theta

Mathematically;

tan theta = 0pposite/adjacent

Sine theta = opposite/hypotenuse

Firstly we need the length of the hypotenuse

This can be obtained using the Pythagoras’ theorem which states that the square of the hypotenuse equals sum of the squares of the two other sides.

Let’s call the hypotenuse h

h^2 = 3^2 + 4^2

h^2 = 9 + 16

h^2 = 25

h = √(25)

h = 5

Now from the tan theta, we know that the opposite is 3

Thus, the value of the sine theta = 3/5 or simply 0.6

5 0

3 years ago

How much longer is a 2 1/2 inch long piece of string than a 2/5 long piece of string

Rashid [163]

It is 2.1 inches longer. Plz plz plz give me brainiest answer I only need 3 more to rank up. If u do I will show my work and show the answer as a fraction.

4 0

3 years ago

Read 2 more answers