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The first mechanic worked for 10 hours and the second mechanic worked for 15 hours.
Step-by-step explanation:
Given,
Charges of first mechanic = $95 per hour
Charges of second mechanic = $115 per hour
Total hours = 25
Total amount charged = $2675
Let,
The number of hours worked by first mechanic = x
The number of hours worked by second mechanic = y
According to given statement;
x+y=25 Eqn 1
95x+115y=2675 Eqn 2
Multiplying Eqn 1 by 95
Subtracting Eqn 3 from Eqn 2
Dividing both sides by 20
Putting y=15 in Eqn 1
The first mechanic worked for 10 hours and the second mechanic worked for 15 hours.
Keywords: linear equation, elimination method
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Answer:
and
The null hypothesis is not rejected
Step-by-step explanation:
Given
Random sample of 50 commuter times
Solving (a): The null and alternate hypothesis
From the question, a previous census shows that:
and
This is the null hypothesis i.e.
Reading further, a new test was to show whether the average has decreased.
This is the alternate hypothesis, and it is represented as:
Solving (b) and (c): The test statistic (T).
This is calculated using:
In this case:
and
So:
Solving (c): Accept or reject null hypothesis
First calculate the degrees of freedom (df)
From the t distribution table,
At: ,
and
the t score is:
<em>So, the null hypothesis is not rejected</em>