Question

If y varies directly as x and given y =9 when x= 5, fInd:

Answer 1

Step-by-step explanation:

The statement

y varies directly as x is written as

$y \: \: \alpha \: \: x$

So we have

y = kx

First of all we must find the relationship between them

when

x = 5 and y = 9

We have

9 = 5k

Divide both sides by 5

$k = \frac{9}{5}$

So the equation for the variation is

$y = \frac{9}{5} x$

b).

when x = 15

$y = \frac{9}{5} \times 15 \\ = 9 \times 3$

We have the answer as

y = 27

c).

when y = 6

$6 = \frac{9}{5} x \\ 30 = 9x \\ x = \frac{30}{9}$

We have the answer as

$x = \frac{10}{3}$

Hope this helps you