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notsponge [240]
3 years ago
14

Every train carriage has 4 doors how many doors will the train have if there are 7 carriages

Mathematics
2 answers:
s2008m [1.1K]3 years ago
5 0

Answer: 28

Step-by-step explanation:

4*7=28

lianna [129]3 years ago
5 0

First write down the unit ratio that is involved.

In this case, it's <em>train carriage/doors</em>.

Next, we set up our proportion.

We know that for every train carriage, there are 4 doors.

So we have 1/4.

We are asked how many doors will there be is there are 7 carriages.

So we have 7/x.

The 7 must go on the top because our unit ratio says

that we must put train carriage/doors.

So we have 1/4 = 7/x.

Solving from here, we use the means-extremes property.

This states that the product of the extremes, (1)(x),

equals the product of the means, (4)(7).

So we have 1x = 28 or just x = 28.

This means that for 7 carriages, there are 28 doors.

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g A popular theory is that presidential candidates have an advantage if they are taller than their main opponents. Listed are he
stira [4]

Answer:

Step-by-step explanation:

Corresponding heights of presidents and height of their main opponents form matched pairs.

The data for the test are the differences between the heights.

μd = the​ president's height minus their main​ opponent's height.

President's height. main opp diff

191. 166. 25

180. 179. 1

180. 168. 12

182. 183. - 1

197. 194. 3

180. 186. - 6

Sample mean, xd

= (25 + 1 + 12 - 1 + 3 + 6)/6 = 5.67

xd = 5.67

Standard deviation = √(summation(x - mean)²/n

n = 6

Summation(x - mean)² = (25 - 5.67)^2 + (1 - 5.67)^2 + (12 - 5.67)^2+ (- 1 - 5.67)^2 + (3 - 5.67)^2 + (- 6 - 5.67)^2 = 623.3334

Standard deviation = √(623.3334/6 sd = 10.19

For the null hypothesis

H0: μd ≥ 0

For the alternative hypothesis

H1: μd < 0

The distribution is a students t. Therefore, degree of freedom, df = n - 1 = 6 - 1 = 5

The formula for determining the test statistic is

t = (xd - μd)/(sd/√n)

t = (5.67 - 0)/(10.19/√6)

t = 1.36

We would determine the probability value by using the t test calculator.

p = 0.12

Since alpha, 0.05 < than the p value, 0.12, then we would fail to reject the null hypothesis.

Therefore, at 5% significance level, we can conclude that for the population of heights for presidents and their main​ opponents, the differences have a mean greater than 0 cm.

5 0
3 years ago
Which expression is equivalent to 4(7 + 8)? (3 points) 11 + 8 11 + 12 28 + 12 28 + 32
sergij07 [2.7K]

Answer:

D) 28+32

Step-by-step explanation:

Well, if you solve the equation in the question, you derive 60.

So, solve all of the equations in the answer, and you find that the last answer choice is the only one that equals 60.

Hope this helped.

7 0
4 years ago
Read 2 more answers
The value of n from the set {6, 7, 8, 9} that holds true for 4n − 12 &lt; 2n + 2 is .
IrinaVladis [17]

Answer:

6

Step-by-step explanation:

4n - 12 < 2n + 2 is for n=6

4×6 -12 < 2×6 +2

24 - 12 < 12 + 2

12 < 14 correct

for n=7

4×7 - 12 < 2×7 + 2

16 < 16 incorrect

for n=8

4×8 - 12 < 2×8 + 2

20 < 18 incorrect

for n=9

4×9 - 12 < 2×9 + 2

24 < 20 incorrect

so, only for n=6 is the expression true.

3 0
2 years ago
77- -145= 77 minus negative 145 =
ololo11 [35]
77 - (-145) = 77 + 145 = 222
7 0
3 years ago
Read 2 more answers
1.<br> What is the equation of a circle with center (-5, 8) and radius 9?
miss Akunina [59]

Answer:

Your equation is:

(x−5)2+(y+8)2=92

Expanding from general form you can write this as:

x2−10x+y2+14y+−8=0

Step-by-step explanation:

i think its correct ig don't know sry but i tried hope it helps you ✨

8 0
3 years ago
Read 2 more answers
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