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3 years ago

The ratio of boys to girls is 3 to 2 if there are 12 boys how many girls are there

Mathematics

2 answers:

aalyn [17]3 years ago

5 0

There are 8 girls because 3×4=12 so 2×4=8

lana [24]3 years ago

3 0

You just have to divide 12 by 3 and multiply the quotient by the number of girls.

$12/3=4$

$4*2=8$

There 8 girls.

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Answer:

x=57

Step-by-step explanation:

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An oil tank has to be drained for maintenance. The tank is shaped like a cylinder that is 5 ft long with a diameter of 1.8 ft .

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2 years ago

A survey was conducted to determine the amount of time, on average, during a given week SCAD students spend outside of class on

fiasKO [112]

Answer:

Standard Deviation = 5.928

Step-by-step explanation:

a) Data:

Days Hours spent (Mean - Hour)²

1 5 61.356

2 7 34.024

3 11 3.360

4 14 1.362

5 18 26.698

6 22 84.034

6 days 77 hours, 210.834

mean

77/6 = 12.833 and 210.83/6 = 35.139

Therefore, the square root of 35.139 = 5.928

b) The standard deviation of 5.928 shows how the hours students spend outside of class on class work varies from the mean of the total hours they spend outside of class on class work.

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3 years ago

The following data on average daily hotel room rate and amount spent on entertainment (The Wall Street Journal, August 18, 2011)

Zielflug [23.3K]

Answer:

a. Predicted Amount = $109.46

b. Confidence Interval = (94.84,124.08)

c. Interval = (110.6883,188.8517)

Step-by-step explanation:

Given

ŷ = 17.49 + 1.0334x.

SSE = 1541.4

ŷ = 17.49 + 1.0334(89)

ŷ = 109.4626

ŷ = 109.46 --- Approximated

Predicted Amount = $109.46

ŷ = 17.49 + 1.0334(89)

ŷ = 109.4626

ŷ = 109.46

First we calculate the standard deviation

variance = SSE/(n-2)

v = 1541.4/(9-2)

v = 1541.4/7

v = 220.2

s = √v

s = √220.2

s = 14.839

Then we calculate mean(x) and ∑(x - (mean(x))²

X --- Y -- Mean(x) --- ∑(x - (mean(x))²

148 -- 161 -- 43-- 1849

96 || 105|| -9 || 81

91 ||101 || -14 || 196

110 || 142 || 5 || 25

90 || 100 || -15 || 225

102 || ||120 ||-3|| 9

136 || 167 ||31 ||961

90 || 140 ||-15 ||225

82 || 98 ||-23 || 529

Sum 945 || 1134|| 0 ||4100

Mean (x) = 945/9 = 105

∑(x - (mean(x))² = 4100

α = 1 - 95% = 5%

α/2 = 2.5% = 0.025

tα,df = n − 2 = t0.025,7 =2.365

Confidence interval = 109.46 ± 2.365 * 14.839 √((1/9)+ (89-105)²/4100

Confidence Interval = (109.46 ± 14.62)

Confidence Interval = (94.84,124.08)

ŷ = 17.49 + 1.0334(128)

ŷ = 149.7652

ŷ = 149.77

Interval = 149.77 ± 2.365 * 14.839 √((1/9)+ (128-105)²/4100

Interval = 149.77 ± 39.0817

Interval = (110.6883,188.8517)

3 0

3 years ago