Question

If y varies directly as x and y = 8 when x = 2, then does y = 3 when x = 12

Answer 1

the initial statement is

y

∝

x

to convert to an equation multiply by k the constant

of variation

⇒

y

=

k

x

to find k use the given condition

y

=

3

when

x

=

2

y

=

k

x

⇒

k

=

y

x

=

3

2

equation is

¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

∣

∣

∣

2

2

y

=

3

2

x

2

2

∣

∣

∣

−−−−−−−−−−−−

when

x

=

8

then

y

=

3

2

1

×

8

4

=

3

×

4

=

12

Explanation: