4x + 7y = -30
How can you order a ladder?
y = 3 when x = 5, find x when y = 2.5
Answer:
Step-by-step explanation:
From the law of variation,
y <> 1/x, where <> is the constant of proportionality. Therefore
y = k/x where k is a constant
3 = k/5 and k = 15
To find x when y = 2.5(5/2)
Go back to the second equation
y = k/x
5/2 = 15/x
When you cross multiply
5x = 30.
Divide through by 5,
x = 6.
Answer:
Let charge per day be $x and charge per mile be $y
then:
as per the given condition we have;
3x + 300y =159 .....[1]
5x + 600y = 289 .....[2]
Multiply equation [1] both sides by 5 we get;
Using distributive property:
15x+1500y = 795 .....[3]
Multiply equation [2] by 3 both sides we get;
Using distributive property:
15x+1800y = 867 .....[4]
Subtract equation [3] from [4] to eliminate x and solve for y;
15x+1800y-15x-1500y = 867 -795
Combined like terms;
300y = 72
Divide both sides by 300 we get;
⇒ y =$0.24 per mile.
Now substitute this value y in equation [1] to solve for x;
3x + 300(0.24) =159
3x + 72 =159
Subtract 72 both sides we get;
3x + 72 -72 = 159 -72
Simplify:
3x = 87
Divide both sides by 3 we get;
Therefore, the best rental charges per day is, $ 29 and the charges per mile is, $0.24