Answer:
13 children and 9 adults if the total cost is $152.5
Step-by-step explanation:
Let x children and y adults
x + y = 22 (1)
5.5x + 9y = 125.5 (2)
y = 22 - x
5.5x + 9(22 - x) = 125.5
5.5x + 198 - 9x = 125.5
-3.5x = 125.5 - 198
-3.5x = -72.5
x = 20.7
y = 22 - x = 1.3
Which is not possible
If the total cost is $152.5
x + y = 22 (1)
5.5x + 9y = 152.5 (2)
y = 22 - x
5.5x + 9(22 - x) = 152.5
5.5x + 198 - 9x = 152.5
-3.5x = 152.5 - 198
-3.5x = -45.5
x = 13
y = 22 - 13 = 9
So an exponential equation is gonna be used for this problem. The formula for such is
, in which the a variable is the initial value and the b variable is the growth/decay rate.
For this situation, 1200 is gonna be your a variable since you've started out with it. And as for your b variable, its gonna be 107.3%, or 1.073, since it's increasing.
Your equation should look like this:
and from here just plug in 10 into the x variable and solve.
Multiply (1.073)^10 (don't round answers until the end), and take that answer and multiply it with 1200, your answer should be $2427.61.
Answer: the rate at which the distance between the boats is increasing is 68 mph
Step-by-step explanation:
The direction of movement of both boats forms a right angle triangle. The distance travelled due south and due east by both boats represents the legs of the triangle. Their distance apart after t hours represents the hypotenuse of the right angle triangle.
Let x represent the length the shorter leg(south) of the right angle triangle.
Let y represent the length the longer leg(east) of the right angle triangle.
Let z represent the hypotenuse.
Applying Pythagoras theorem
Hypotenuse² = opposite side² + adjacent side²
Therefore
z² = x² + y²
To determine the rate at which the distances are changing, we would differentiate with respect to t. It becomes
2zdz/dt = 2xdx/dt + 2ydy/dt- - - -- - -1
One travels south at 32 mi/h and the other travels east at 60 mi/h. It means that
dx/dt = 32
dy/dt = 60
Distance = speed × time
Since t = 0.5 hour, then
x = 32 × 0.5 = 16 miles
y = 60 × 0.5 = 30 miles
z² = 16² + 30² = 256 + 900
z = √1156
z = 34 miles
Substituting these values into equation 1, it becomes
2 × 34 × dz/dt = (2 × 16 × 32) + 2 × 30 × 60
68dz/dt = 1024 + 3600
68dz/dt = 4624
dz/dt = 4624/68
dz/dt = 68 mph
12/16
If you divide 12 by 4 you get 3 and if you divide 16 by 4 you get 4 so that would be 3/4
