29. A carpenter worked for 4 days to finish a repair job. She charged $825 for 15 hours plus $278 for materials. What is the carpenter's rate per hour?
Let’s start solving:
=> 825 dollars + 278 dollars = 1 103 dollars is the total payment a carpenter have received
=> 15 hours is the total hours he worked
=> 1 103 / 15 = 73.5 dollars per hour. This is already including the material or equipment fee.
Answer:
-23, -15, -10, -7, -3, -2, -1, 0, 2, 2, 3, 5, 10, 15, 23
Step-by-step explanation:
:)
Answer:
I think your correct
Step-by-step explanation:
Answer:
It'll take approximately 9.1 minutes
Step-by-step explanation:
The decay of this element can be modeled by the following expression:
m(t) = 540*(1 - 0.179)^t
Where m is the mass of the element in a given minute t. This expression comes from a compounded interest formula, with negative rate, since they will work in the same manner. Therefore to find how long until it reaches 90 g, we need to make m = 90 and solve for t.
90 = 540*(0.821)^t
(0.821)^t = 90 / 540
(0.821)^t = 1/6
ln(0.821^t) = ln(1/6)
t*ln(0.821) = ln(1) - ln(6)
t*ln(0.821) = - ln(6)
t = -ln(6)/ln(0.821) = 9.08452
It'll take approximately 9.1 minutes
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