P + t = 140
t = p - 4 or p - t = 4
answer is A first one
Answer:
The answer is when they work 4 hours x=4
Step-by-step explanation:
510 + 80x = 650 + 45x
80x - 45x = 650 - 510
35x = 140
x = 140/35
x = 4 hours
Answer: 
Step-by-step explanation:
By definition, the perimeter of a rectangle is:

Where "l" is the lenght and "w" is the width.
If you solve for "l":

In this case, you know that the following expression represents the perimeter of the rectangle:

And the width of that rectanle is represented wih this expression:

Therefore, based on the explained above, you can conclude that the lenght of that rectangle is given by:

Finally, simplifying the expression, you get:

To Find :
Position vector at time
and
.
Solution :
r (t) = 2 (t −7)i + 12t j
Putting t = 5 s and t = 8 s, we get :
r(5) = 2( -2 )i + 60j
r(5) = -4i + 60j
r(8) = 2i + 96j
Now, to find speed differentiating the r(t) w.r.t t :

Hence, this is the required solution.
Personally I would say C because when you take good notes you can go over what you don’t remember. You can also use your notes as a study guide.