A number is chosen at random from 1 to 25. Find the probability of selecting a number less than 2
1 answer:
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Answer: 14
<u>Step-by-step explanation:</u>
Consecutive even numbers would be {2, 4, 6, 8, 10, ...}
Let x represent the smallest number, then x + 2 is the middle number and x + 4 is the largest number.
1st number: x
2nd number: x + 2
3rd number: x + 4
1st number + 2nd number + 3rd number = Sum
(x) + (x + 2) + (x + 4) = 48
3x + 6 = 48
3x = 42
x = 14
1st number: x ⇒ x = 14
2nd number: x + 2 ⇒ 14 + 2 = 16
3rd number: x + 4 ⇒ 14 + 4 = 18
<u>Check:</u>
14 + 16 + 18 = 48
Answer:
A. 3.0 m/s
Step-by-step explanation:
Based on the graph,
velocity = Area of the graph
(y : position and x : time)
Let y1 = 2m and y2 = 14m,
t1 = 0s and t2 = 4s
v = (14 - 2)m/(4-0)s
= 12m/4s
= 3.0 m/s
Answer:
Step-by-step explanation:
Use Newton's Law of Cooling for this one. It involves natural logs and being able to solve equations that require natural logs. The formula is as follows:
where
T(t) is the temp at time t
T₁ is the enviornmental temp
T₀ is the initial temp
k is the cooling constant which is different for everything, and
t is the time (here, it's in minutes)
If we are looking first for the temp after 20 minutes, we have to solve for the k value. That's what we will do first, given the info that we have:
T(t) = 80
T₁ = 30
T₀ = 100
t = 5
k = ?
Filling in to solve for k:
which simplifies to
Divide both sides by 70 to get
and take the natural log of both sides:
Since you're learning logs, I'm assuming that you know that a natural log and Euler's number, e, "undo" each other (just like taking the square root of something squared). That gives us:
Divide both sides by 5 to get that
k = -.0672944473
Now that we have a value for k, we can sub that in to solve for T(20):
which simplifies to
On your calculator, raise e to that power and multiply that number by 70:
T(20)= 30 + 70(.260308205) and
T(20) = 30 + 18.22157435 so
T(20) = 48.2°
Now we can use that k value to find out when (time) the temp of the object cools to 35°:
T(t) = 35
T₁ = 30
T₀ = 100
k = -.0672944473
t = ?
which simplifies to
Now divide both sides by 70 and take the natural log of both sides:
which simplifies to
-2.63905733 = -.0672944473t
Divide to get
t = 39.2 minutes