The cost CC (in dollars) for the care and maintenance of a horse and carriage is C=15x+2000C=15x+2000, where xx is the number of
1 answer:
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We are given sides of the triangle by expression
First side : n
Second side : m = 5n-5.
Third side : l = 5/4 m - n.
Perimeter is 90.
Therefore, first equation could be set :
n +m +l = 90 --------------equation(1)
Second equation would be
m = 5n-5 --------------equation(2)
Third equation would be
l = 5/4 m - n --------------equation(3)
Let us solve the system of equations by substitution.
Substituting m = 5n-5 and l = 5/4 m - n in first equation.
We get
n +5n-5 +5/4 m - n= 90
Now, substituting m = 5n-5 in above equation we get
n +5n-5 +5/4 (5n-5) - n= 90
5n + 25n/4 -5 - 25/4 =90
5n + 6.25n -5-6.25 = 90.
11.25n-11.25 = 90
Adding 11.25 on both sides, we get
11.25n-11.25+11.25 = 90+11.25
11.25n = 101.25.
Dividing both sides by 11.25, we get
n=9.
Plugging n=9 in 2nd equation.
m = 5(9)-5 = 45 -5 = 40.
Plugging n=9 and m=40 in first equation, we get
9 +40 +l = 90
49 +l = 90.
Subtracting 49 from both sides, we get
49-49 +l = 90-49
l = 41.
Therefore, sides are of lengths l = 41, m= 40 and n=9.
Answer:
Speed of Current = 5 miles per hour
Step-by-step explanation:
We know distance formula,
D = RT
Where
D is distance
R is rate
T is time
If we let speed of boat (assume) to be "x" and speed of current to be "c"
Then downstream rate is (with current) = x + c
Upstream rate is (against current) = x - c
40 mins to go 20 miles downstream, that means:
D = RT
20 = (x + c)(40)
and
60 minutes to go upstream, 20 miles, that means:
D = RT
20 = (x - c)(60)
Simplifying first equation:
40x + 40c = 20
Simplifying second equation:
60x - 60c = 20
Multiplying first equation by 60, we get:
60 * [40x + 40c = 20] = 2400x + 2400c = 1200
Multiplying second equation by 40, we get:
40 * [60x - 60c = 20] = 2400x - 2400c = 800
Now we add up both these equations:
2400x + 2400c = 1200
2400x - 2400c = 800
----------------------------------
4800x = 2000
x = 2000/4800 = 5/12
We need speed of current, that is "c", so we plug in the value of x into first equation and solve for c:
Speed of Current = 1/12 miles per minute
Since there is 60 minutes in an hours, that would be:
(1/12) * 60 = 5 miles per hour
Speed of Current = 5 miles per hour