Answer: 37
Step-by-step explanation:
Given : Significance level :
Critical value :
margin of error : E= 1 mile per gallon
Population standard deviation: miles per gallon.
We know that when the population standard deviation is known then the formula to find the sample size is given by :
[Round to the next whole number.]
Hence, the required number of automobiles should be used in the test = 37
Using proportions, it is found that the speed of the runners are of 16 mph and of 20 mph.
<h3>What is a proportion?</h3>A proportion is a fraction of a total amount.
After 30 minutes, the runners are 2 miles apart, hence the second runner is 4 miles per hour faster than the second, that is:
.
The first runner's speed is 4/5 of the speed of the second runner, hence:
Hence, the speed of the runners are of 16 mph and of 20 mph.
More can be learned about proportions at brainly.com/question/24863377
1) Given that the apple tree is 4/5 pear tree we can write
Apple Tree size = 4/5 Peartree
Apple tree= 4m
2) So we can write the following expression for that:
So the Pear tree is 5 meters tall, and the apple tree is 4/5*5 = 4 m