7. A vending machine only accepts dimes and quarters. There are 85 coins
1 answer:
There are 55 quarters and 30 dimes in the machine.
Step-by-step explanation:
Total coins = 85
Total amount = $16.75 = 16.75*100 = 1675 cents
1 quarter = 25 cents
1 dime = 10 cents
According to given statement;
x+y=85 Eqn 1
25x+10y=1675 Eqn 2
Multiplying Eqn 1 by 10
Subtracting Eqn 3 from Eqn 2
Dividing both sides by 15
Putting in Eqn 1;
There are 55 quarters and 30 dimes in the machine.
Keywords: linear equation, subtraction
Learn more about linear equations at:
#LearnwithBrainly
You might be interested in
Answer:
a)
And the 99% confidence interval would be given (0.630;0.730).
b) We are 99% confident that the true proportion of infected chickens are between 0.63 (63%) and 0.73 (73%)
c) For this case the answer would be No. Since all the required assumptions in order to construct the confidence interval are satisfied, so then the results can be assumed for all the population
Step-by-step explanation:
Previous concepts
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
represent the real population proportion of interest
represent the estimated proportion
n=575 is the sample size required (variable of interest)
represent the critical value for the margin of error
The population proportion have the following distribution
Part a
The confidence interval would be given by this formula
For the 99% confidence interval the value of and
, with that value we can find the quantile required for the interval in the normal standard distribution.
And replacing into the confidence interval formula we got:
And the 99% confidence interval would be given (0.630;0.730).
Part b
We are 99% confident that the true proportion of infected chickens are between 0.63 (63%) and 0.73 (73%)
Part c
For this case the answer would be No. Since all the required assumptions in order to construct the confidence interval are satisfied, so then the results can be assumed for all the population