Question

If y= 1/5 when x=3, find y when x=4, given that y varies directly with x

Answer 1

Answer:

$y = \frac{4}{15}$

Step-by-step explanation:

To find y when x=4, we must first find the relationship between them

The statement

y varies directly with x is written as

$y \: \: \: \alpha \: \: \: kx$

where k is the constant of proportionality

From the question

when y = 1/5

x = 3

Substitute the values into the above formula and solve

That's

$\frac{1}{5} = 3k \\ 15k = 1 \\ k = \frac{1}{15}$

So the formula for the variation is

$y = \frac{x}{15}$

From the question

when x = 4

$y = \frac{4}{15}$

Hope this helps you