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3 years ago

21.58 correct to 2 decimal places

Mathematics

2 answers:

enot [183]3 years ago

3 0

Answer:

Step-by-step explanation:

its 22.00 or just 22

inna [77]3 years ago

3 0

Hey! :)

First, let's get to know about rounding.

Rounding, let's look at a example of rounding. We have a decimal 23.44 for example, it is not above 50 meaning it rounds to 23.00.

Now, let's look at our equation.

As we can see, 21.58 is above 50 so it rounds to the next number, our answer is 22.00.

Hopefully that's clear!

Have a good one :)

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The increasing annual cost (including tuition, room, board, books, and fees) to attend college has been widely discussed (Time).

NeX [460]

Answer:

(a) PRIVATE COLLEGES

Sample mean is $42.5 thousand

Sample standard deviation is $6.65 thousand

PUBLIC COLLEGES

Sample mean is $22.3 thousand

Sample standard deviation is $4.34 thousand

(b) Point estimate is $20.2 thousand. The mean annual cost to attend private colleges ($42.5 thousand) is more than the mean annual cost to attend public colleges ($22.3 thousand)

(c) 95% confidence interval of the difference between the mean annual cost of attending private and public colleges is $19.2 thousand to $21.2 thousand

Step-by-step explanation:

(a) PRIVATE COLLEGES

Sample mean = Total cost ÷ number of colleges = (51.8+42.2+45+34.3+44+29.6+46.8+36.8+51.5+43) ÷ 10 = 425 ÷ 10 = $42.5 thousand

Sample standard deviation = sqrt[summation (cost - sample mean)^2 ÷ number of colleges] = sqrt([(51.8-42.5)^2 + (42.2-42.5)^2 + (45-42.5)^2 + (34.3-42.5)^2 + (44-42.5)^2 + (29.6-42.5)^2 + (36.8-42.5)^2 + (51.5-42.5)^2 + (43-42.5)^2] ÷ 10) = sqrt (44.24) = $6.65 thousand

PUBLIC COLLEGES

Sample mean = (20.3+22+28.2+15.6+24.1+28.5+22.8+25.8+18.5+25.6+14.4+21.8) ÷ 12 = 267.6 ÷ 12 = $22.3 thousand

Sample standard deviation = sqrt([(20.3-22.3)^2 + (22-22.3)^2 + (28.2-22.3)^2 + (15.6-22.3)^2 + (24.1-22.3)^2 + (28.5-22.3)^2 + (22.8-22.3)^2 + (25.8-22.3)^2 + (18.5-22.3)^2 + (25.6-22.3)^2 + (14.4-22.3)^2 + (21.8-22.3)^2] ÷ 12) = sqrt (18.83) = $4.34 thousand

(b) Point estimate = mean annual cost of attending private colleges - mean annual cost of attending public colleges = $42.5 thousand - $22.3 thousand = $20.2 thousand.

This implies the the mean annual cost of attending private colleges is greater than the mean annual cost of attending public colleges

E = t×sd/√n

Mean = $42.5 - $22.3 = $20.2 thousand

sd = $6.65 - $4.34 = $2.31 thousand

n = 10+12 = 22

degree of freedom = 22-2 = 20

t-value corresponding to 20 degrees of freedom and 95% confidence level is 2.086

E = 2.086×$2.31/√22 = $1.0 thousand

Lower bound = Mean - E = $20.2 thousand - $1.0 thousand = $19.2 thousand

Upper bound = Mean + E = $20.2 thousand + $1.0 thousand = $21.2 thousand

95% confidence interval is $19.2 thousand to $21.2 thousand

6 0

3 years ago

Saul decides to use the IQR to measure the spread of the data. Saul calculates the IQR of the data set to be 27.

padilas [110]

Answer:

Step-by-step explanation:

The IQR is quartile 3 - quartile 1. First, we need to find the mean of the dataset, which is 50 -- the fifth number. Then, the median of the dataset on the left of the fifth number is the first quartile, and the median of the dataset on the right is the third. We get Q1 to then be halfway between 30 and 50, or 40, and Q3 to be halfway between 56 and n, so Q3 = (56+n)/2. Since we need Q3-Q1=27, or (56+n)/2-40=27, we have (56+n)/2=67 and 56+n=134, so n = 134-56=78

3 0

3 years ago

A school had 400 girls last year and the number of boys was 95 more than that of the girls. This year the number of girls had in

STatiana [176]

Answer: The fraction by what the number of boys had been reduced=1/11

Step-by-step explanation:

Step 1: To calculate the number of boys last year.

According to the question,

The number of boys last year= 400+95

The number of boys last year=495

Step 2: To calculate the number of girls this year.

According to the question,

The number of girls this year= 400 + 400*1/5

The number of girls this year= 480

Step 3: To calculate the number of boys this year.

According to the question,

The number of boys this year= 480 – 30

The number of boys this year=450

Step 4: To calculate the fraction by what the number of boys had been reduced.

The number of boys reduced= the number of boys last year - the number of boys this year

The number of boys reduced= 495 - 450 = 45

The fraction by what the number of boys had been reduced

= The number of boys reduced/the number of boys last year

Therefore,

The fraction by what the number of boys had been reduced= 45/495= 1/11

6 0

3 years ago

Read 2 more answers

Solve for x. 2 1/2x−3/4(2x+5)=3/8<br><br> Please hurry

Fofino [41]

Answer:

x= - 1.48 or 0.48

Step-by-step explanation:

I used general formula. Hope I'm on a right path.

8 0

3 years ago

1)a chord of length 18cm midway the radius of a circle. calculate the radius of the circle correct to 1d.p. 2)if two parallel ch

kykrilka [37]

Part 1:

Given that the length of the chord is 18 cm and the chord is midway the radius of the circle.

Thus, half the angle formed by the chord at the centre of the circle is given by:

$\cos\theta=\frac{\left( \frac{1}{2} r\right)}{r}= \frac{1}{2} \\ \\ \Rightarrow\theta=\cos^{-1}\left( \frac{1}{2} \right)=60^o$

Now,

$\sin60^o= \frac{9}{r} \\ \\ \Rightarrow r= \frac{9}{\sin60^o} =10.392$

Therefore, the radius of the circle is 10.4 cm to 1 d.p.

Part 2I:

Given that the radius of the circle is 10 cm and the length of chord AB is 8 cm. Thus, half the length of the chord is 4cm. Let the distance of the mid-point O to /AB/ be x and half the angle formed by the chord at the centre of the circle be θ, then

$\sin\theta= \frac{4}{10} = \frac{2}{5} \\ \\ \theta=\sin^{-1}\left( \frac{2}{5} \right)=23.6^o$

Now,

$\cos23.6^o= \frac{x}{10} \\ \\ \Rightarrow x=10\cos23.6^o=9.165\approx9.2cm$

Part 2II:

Given that the radius of the circle is 10cm and the angle distended is 80 degrees. Let half the length of chord CD be y, then:

$\sin40^o= \frac{y}{10} \\ \\ \\ \Rightarrow y=10\sin40^o=6.428$

Thus, the length of chord CD = 2(6.428) = 12.856 which is approximately 12.9 cm.

3 0

3 years ago