If there are 49 students in a class 32 are girls and 17 are boys what percent are boys

Kevin and Randy Muise have a jar containing 73 ?coins, all of which are either quarters or nickels. The total value of the coins

inna [77]

Answer:

24 quarters and 49 nickels

Step-by-step explanation:

This situation has two unknowns - the total number of nickels and the total number of quarters. Because we have two unknowns, we will write a system of equations with two equations using the two unknowns.

n+q=73 is an equation representing the total number of coins
0.05n+0.25q=8.45 is an equation representing the total value in money based on the number of coin. 0.05 and 0.25 come from the value of a nickel and quarter individually.

We write the first equation in terms of q by subtracting it across the equal sign to get n=73-q. We now substitute this for n in the second equation.

0.05(73-q)+0.25q=8.45

3.65-0.05q+0.25q=8.45

3.65+0.20q=8.45

After simplifying, we subtract 3.65 across and divide by the coefficient of q.

0.20q=4.8

q=24

We now know of the 73 coins that 24 are quarters. To find the number of nickels, we subtract 24 from 73 and get 49 nickels.

4 0

3 years ago

Need help with circle measurements in Geometry.

Ymorist [56]

I got 0.999 which is 999/1000

5 0

3 years ago

Max bought twice the amount of apples that Jenna bought. Together they bought 18 pounds of apples. How many pounds of apples did

Natali5045456 [20]

2x+x=18

Max bought 12 apples and Jenna bought 6

6 0

3 years ago

In 1925, airplane engines were cooled with water. Water freezes at a temperature of 32º Fahrenheit. Average winter low temperatu

Snezhnost [94]

Answer:

From November to March, the temperature in Alaska is between 0°F/-18°C and -30°F/-35°C, which is very cold. May and September are both often the driest and the wettest months in Alaska's summer.

I hope this helps you

:)

5 0

2 years ago

In a study of 346 comma 145 cell phone users, it was found that 26 developed cancer of the brain or nervous system. Assuming th

Y_Kistochka [10]

Answer:

a) P ( X ≤ 26 ) = 0.0134

b) The significance of the cell phone causing brain cancer is 1.34 or 0.0134

Step-by-step explanation:

Solution:-

- From the entire population of cell phone users os size N = 346,145 media reported n = 26 people who developed cancer of brain or nervous system.

- The probability of a person developing cancer of the brain or nervous system, assuming that cell phones have no effect, is p = 0.000113.

- Denote a random variable X: The number people who developed cancer of brain or nervous system are normally distributed.

- The expected or mean number of people who developed cancer of brain or nervous system are u = 40.

- The standard deviation ( s ) for the distribution would be:

$s = \sqrt{u*( 1 - p ) }\\\\s = \sqrt{40*( 1 - 0.000113 ) }\\\\s = 6.3242\\$

- The random variate X follows normal distribution with parameters:

X ~ Norm ( 40 , 6.3242^2 )

- The probability of X ≤ 26 cases from the total population of N = 346,145 can be determined by evaluating the Z-score standard value of the test statistics:

$P ( X \leq 26 ) = P ( Z \leq [ \frac{X - u }{s} ) \\\\P ( Z \leq [ \frac{ 26 - 40 }{6.3242} ) = P ( Z \leq -2.21371 )$

- Using standard normal table compute the probability on the left side of Z-score value -2.21371. Hence,

P ( X ≤ 26 ) = 0.0134

- The probability of the less than 26 number of cases who developed cancer of the brain or nervous system is 0.0134 as per media reports.

- So 1.34% of population is a case brain cancer due to cell phones according to media reports.

Which is significant less than the expected number of cases ( 40 ) that occur regardless of cell phone effect.

Answer: The significance of the cell phone causing brain cancer is 1.34 or 0.0134.

5 0

3 years ago