Answer:
4 hours
Step-by-step explanation:
For three visits, the electrician earned $40 × 3 = $120 in "per-visit" charges. For working x hours, he earned 20x in "per-hour" charges. The total of these came to 50x:
120 +20x = 50x
120 = 30x . . . . . . . . subtract 20x
4 = x . . . . . . . . . . . . . divide by 30
The electrician worked 4 hours that day.
Answer:

Step-by-step explanation:
Since we have given that
A toy manufacturer claims that the mean time that its top-selling toy captures children's attention is at least 45 minutes.
Since we need to carry out a hypothesis test whether he can refute the claim.
We always take the alternate hypothesis such that it should satisfy the given statement.
And the null hypothesis can be equal to mean or other than that is given in alternate hypothesis.
So, hypothesis :

Answer: d = 42/r - 6m/r
Step-by-step explanation: Isolate the variable by dividing each side by factors that don't contain the variable.
Answer:
y=7
Step-by-step explanation:
-6y= -27-15
-6y= -42
y=7