Answer:
Speed of the river =
km per hour
Step-by-step explanation:
Speed of the boat in still water = 4 km per hour
Let the speed of the river = v km per hour
Speed of the boat upstream = (4 - v) km per hour
Time taken to cover 6 km = 
=
hours
Speed of the boat downstream = (4 + v) km per hour
Time taken to cover 12 km =
hours
Since, time taken by the boat in both the cases is same,

6(4 + v) = 12(4 - v)
24 + 6v = 48 - 12v
12v + 6v = 48 - 24
18v = 24
v = 
v =
km per hour
I’m believe it’s the 3rd one but i’m not sure
Step-by-step explanation:
Claim: There's 14 Goats and 9 Chickens!!
Data:
Working with the Provided Information.
Let the Number of goats be x
let the Number of Chickens be y
x + y = 23..... (i)
Since the goat Possesses Two Pair of Legs... Which is a Total of 4 Legs... We say Let its Contribution be 4x.
The Chicken has Only a Pair Of Legs...Which is a total of 2 legs.... We say let its contribution be 2y
4x + 2y = 74 .....(ii)
BRINGING BOTH EQUATIONS TOGETHER.
x + y = 23
4x + 2y = 74
From Eqn i
x= 23 - y
Substitute into eqn ii
4(23 - y ) + 2y = 74
92 - 4y + 2y = 74
92 - 2y = 74
2y = 92 - 74
2y = 18
y= 9.
Substitute y into any of the eqns to get x
x + y = 23
x + 9=23
x = 23 - 9
x = 14
This simply proves that there are 14 Goats and 9 Chickens!!!.
HAVE A GREAT DAY!
The number of mole of pure 11C (carbon-11) initially present is 0.2727 mole
<h3>Description of mole </h3>
The mole of a substance is related to it's mass and molar mass according to the following equation
Mole = mass / molar mass
With the above formula, we can obtain the number of mole of pure 11C. Detail below:
<h3>How to determine the mole of 11C</h3>
From the question given, the following data were obtained:
- Molar mass of 11C = 11 g/mol
- Mass of 11C = 3 g
- Mole of 11C =?
Mole = mass / molar mass
Mole = 3 / 11
Mole = 0.2727 mole
Therefore, the number of mole of pure 11C initially present is 0.2727 mole
Learn more about mole:
brainly.com/question/13314627
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I believe you meant f(x) = x^2 - 3x - 10.
f(b) - f(a)
The ave. r. of c. formula is a. r. c = -----------------
b -a
(6)^2 - 3(6) - 10 - [(4)^2 - 3(4) - 10]
Here, a. r. c. = ------------------------------------------------------
6-4
36 - 18 -10 - 16 + 12 + 10
... which comes out to ---------------------------------------
2
a. r. c. = 7 for x^2 - 3x - 10 on the interval [4,6]