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3 years ago

Help me with 18 19 and 20 plz

Mathematics

1 answer:

Rzqust [24]3 years ago

6 0

19: He multiplied instead of dividing which will make a totally incorrect answer

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Help me please thanks

Tems11 [23]

Answer:

-5; -4

Step-by-step explanation:

you are welcome

8 0

3 years ago

Read 2 more answers

Work out the area of ABCD.<br> Give your answer to 1 decimal place.

Mashutka [201]

Answer:

A is 90

C is 65

Step-by-step explanation:

6 0

3 years ago

Answer pls lol. also please make sure to explain it!

o-na [289]

Answer:

He made 5 2-pointers and 4 3-pointers

Step-by-step explanation:

Let x = number of 2-pointers he scored.

Let y = number of 3 pointers he scored.

The total number of shots he made is x + y, and it it equals 9.

The first equation is

x + y = 9

The total number of points he scored on 2-pointers is 2x. The total number of points he scored on 3-pointers is 3y. The total number of points he scored with 2-pointers and 3-pointers is 2x + 3y. It equals 22.

The second equation is

2x + 3y = 22

We have a system of 2 equations.

x + y = 9

2x + 3y = 22

We will use the substitution method.

Solve the first equation for x.

x = 9 - y

Now substitute 9 - y in for x in the second equation.

2x + 3y = 22

2(9 - y) + 3y = 22

18 - 2y + 3y = 22

y + 18 = 22

y = 4

Now we substitute 4 for y in the first equation and solve for x.

x + y = 9

x + 4 = 9

x = 5

Answer: He made 5 2-pointers and 4 3-pointers

Check:

5 2-pointers and 4 3-popinters are a total of 9 shots, so the number of shots is correct.

Now we check the number of points.

5 * 2 + 4 * 3 = 10 + 12 = 22

22 points is the correct total.

Our answer is correct.

8 0

2 years ago

A population is estimated to have a standard deviation of 9. We want to estimate the population mean within 2, with a 99% level

cupoosta [38]

Answer:

The sample required is $n = 135$

Step-by-step explanation:

From the question we are told that

The standard deviation is $\sigma = 9$

The margin of error is $E = 2$

Given that the confidence level is 99% then the level of significance is mathematically evaluated as

$\alpha = 100-99$

$\alpha = 1 \%$

$\alpha = 0.01$

Next we will obtain the critical value $\frac{\alpha }{2}$ from the normal distribution table(reference math dot armstrong dot edu) , the value is

$Z_{\frac{\alpha }{2} } = Z_{\frac{0.05 }{2} } = 2.58$

The sample size is mathematically represented as

$n = [ \frac{Z_{\frac{\alpha }{2} } * \sigma }{E} ]^2$

substituting values

$n = [ \frac{ 2.58 * 9 }{2} ]^2$

$n = 135$

3 0

3 years ago

The circumference of a circle is 15 centimeters. What is the diameter? Round to the nearest hundredths place.

lesya692 [45]

Answer:

4.77

Step-by-step explanation:

because Circumference can be found with this equation

C = 2piR

we need to plug in 15 for Circumference and solve for its radius or R.

15 = 2piR

15/2pi = R

but we need diameter which is 2R so we just need to multiply the answer by 2.

15/2pi × 2 = Diameter

15/pi = D

approximately = 4.77

6 0

3 years ago