Bert's age plus twice Ernie's age is 30. Three times Bert's age plus 8 times Ernie's age is 108. How old are Bert and Ernie?

Leonard and Liam each own a collection of vintage cars. Leonard has 7 cars more than Liam has. Three times the number of cars Le

dimulka [17.4K]

Answer: The answer is (22, 15).

Step-by-step explanation: Given that 'x' represents the number of cars Leonard has and 'y' represents the number of cars Liam has.

Then, according to the given information, we have

$x-y=7,\\\\3x+2y=96.$

Multiplying the first equation by 2 and adding to the second equation, we have

$2x+3x=14+96\\\\\Rightarrow 5x=110\\\\\Rightarrow x=22.$

So,

$y=x-7=22-7=15.$

Therefore, Leonard has 22 cars and Liam has 15 cars.

Thus, (22, 15) is the solution to the given system.

5 0

2 years ago

Read 2 more answers

A skyscraper has 49 floors there are 26 offices on each of the bottom 31 fours the top 18 floors each have 38 officers about how

Anettt [7]

Answer:

903 offices

Step-by-step explanation:

Total number of officers in the sky scraper

= 26 + 31 + [(49-2)×18]

= 26 + 31 + 846

= 903 offices

3 0

2 years ago

What should I buy? A study conducted by a research group in a recent year reported that of cell phone owners used their phones i

Llana [10]

Answer:

The probability that seven or more of them used their phones for guidance on purchasing decisions is 0.7886.

Step-by-step explanation:

The question is incomplete:

What should I buy? A study conducted by a research group in a recent year reported that 57% of cell phone owners used their phones inside a store for guidance on purchasing decisions. A sample of 14 cell phone owners is studied. Round the answers to at least four decimal places. What is the probability that seven or more of them used their phones for guidance on purchasing decisions?

We can model this as a binomial random variable, with p=0.57 and n=14.

$P(x=k)=\dbinom{n}{k} p^{k}q^{n-k}$

a) We have to calculate the probability that seven or more of them used their phones for guidance on purchasing decisions:

$P(x\geq7)=\sum_{k=7}^{14}P(x=k)\\\\\\$

$P(x=7)=\dbinom{14}{7} p^{7}q^{7}=3432*0.0195*0.0027=0.1824\\\\\\P(x=8) = \dbinom{14}{8} p^{8}q^{6}=3003*0.0111*0.0063=0.2115\\\\\\P(x=9) = \dbinom{14}{9} p^{9}q^{5}=2002*0.0064*0.0147=0.1869\\\\\\P(x=10) = \dbinom{14}{10} p^{10}q^{4}=1001*0.0036*0.0342=0.1239\\\\\\P(x=11) = \dbinom{14}{11} p^{11}q^{3}=364*0.0021*0.0795=0.0597\\\\\\P(x=12) = \dbinom{14}{12} p^{12}q^{2}=91*0.0012*0.1849=0.0198\\\\\\P(x=13) = \dbinom{14}{13} p^{13}q^{1}=14*0.0007*0.43=0.004\\\\\\$

$P(x=14) = \dbinom{14}{14} p^{14}q^{0}=1*0.0004*1=0.0004\\\\\\$

$P(x\geq7)=0.1824+0.2115+0.1869+0.1239+0.0597+0.0198+0.004+0.0004\\\\P(x\geq7)=0.7886$

7 0

2 years ago

Find the exact area of the sector of the circle with the following radius and central angle

Lostsunrise [7]

THe area of the whole circle is pi r^2 = 6^2 * pi = 36pi

There are 360 degrees in a crcle so this sectors area i (30/360) *36pi

= 3 pi

5 0

3 years ago

A music buff wants to estimate the percentage of students at a midwestern university who believe that elvis is still alive. how

gulaghasi [49]

Since we are not given any information about the proportion, we will assume the sample proportion to be 0.50

so,
p = 0.50
The Error is 10% percentage point. This means that on either side of the population proportion the error is 5% so E = 0.05
z = 1.645 (Z value for 90% confidence interval)

The margin of error for population proportion is calculated as:

$E=z* \sqrt{ \frac{p(1-p)}{n} } \\ \\ 
 \frac{E}{z} = \sqrt{ \frac{p(1-p)}{n} } \\ \\ 
( \frac{E}{z} )^{2}= \frac{p(1-p)}{n} \\ \\ 
n= p(1-p)* (\frac{z}{E})^{2} \\ \\ 
n=271$

This means 271 students should be included in the sample

5 0

3 years ago