The mean weight of the packages is 2.5, so the total weight of the packages is found by multiplying 2.5 pounds by 4 which is equal to 10 pounds. That is the tial weight of the four books. To find the weight of the fourth book, the three other weights are subtracted from 10 pounds:
It would be 270,725. The last choice.
Here u gooo hope this helps
Answer:
8.06
Step-by-step explanation:
So for this one we are just going to take the two points (0,0) and (8,1), and plug them into the formula for distance which is d=
=8.06226
Then just round it
8.06
S = d/t
st = d
t = d/s
The time going is t1.
The time returning is t2.
The total time is 4 hours, so we have t1 + t2 = 4
The speed of the current is c.
The speed going is 9 + c.
The speed returning is 9 - c.
t1 = 16/(9 + c)
t2 = 16/(9 - c)
t1 + t2 = 16/(9 + c) + 16/(9 - c)
4 = 16/(9 - c) + 16/(9 + c)
1 = 4/(9 - c) + 4/(9 + c)
(9 + c)(9 - c) = 4(9 - c) + 4(9 + c)
81 - c^2 = 36 - 4c + 36 + 4c
81 - c^2 = 72
c^2 = 9
c^2 - 9 = 0
(c + 3)(c - 3) = 0
c + 3 = 0 or c - 3 = 0
c = -3 or c = 3
We discard the negative answer, and we get c = 3.
The speed of the current is 3 mph.
