1.If m varies directly as y and m is 6 when y is 36, find the constant of variation.


2. A varies directly as b. If A = 3 when b = 24, find b when A = 10.







3. If y varies inversely with x, and y = 5 when x = 8, what is k?







4. If y varies inversely with x and k = 0.32, what is x when y = 10?


Respuesta :

Answer:

1) the constant of variation is 1/6

2) b=80 when A=10

3)the value of k is 40

4) x=0.032 when y = 10

Step-by-step explanation:

1)m varies directly as y

[tex]\Rightarrow m \propto y \\\Rightarrow m =ky[/tex]

k is the constant of variation

We are given that m is 6 when y is 36

[tex]\Rightarrow 6=k(36)\\\Rightarrow \frac{6}{36}=k\\\Rightarrow \frac{1}{6}=k[/tex]

Hence  the constant of variation is 1/6

2)A varies directly as b.

[tex]\Rightarrow A \propto b\\\Rightarrow A =kb[/tex]

k is the constant of variation

We are given that A = 3 when b = 24

[tex]\Rightarrow 3=k(24)\\\Rightarrow \frac{3}{24}=k\\\Rightarrow \frac{1}{8}=k\\So,A=\frac{1}{8}b[/tex]

Substitute A=10

[tex]10=\frac{1}{8}b[/tex]

80=b

So, b=80 when A=10

3)y varies inversely with x

[tex]\Rightarrow y \propto \frac{1}{x}\\\Rightarrow y = \frac{k}{x}[/tex]

k is the constant of variation

We are given that y = 5 when x = 8

[tex]\Rightarrow 5 = \frac{k}{8}\\\Rightarrow 40=k[/tex]

So, the value of k is 40

4)y varies inversely with x

[tex]\Rightarrow y \propto \frac{1}{x}\\\Rightarrow y = \frac{k}{x}[/tex]

k is the constant of variation

We are given that k=0.32

[tex]\Rightarrow y = \frac{0.32}{x}[/tex]

Substitute y = 10

[tex]\Rightarrow 10 = \frac{0.32}{x}\\\Rightarrow x = 0.032[/tex]

So, x=0.032 when y = 10