Question

If y varies directly as x, and y is 6 when x is 72, what is the value of y when x is 8?

O
61
9
2/3
54
96

Answer 1

y = 2/3 when x = 8.

Explanation:

General equation for direct variation:

The general equation for direct variation is given by:

y = kx, where:

• y varies directly as x,
• and k is the constant of proportionality.

Finding the constant of proportionality (k):

We can first find k by substituting 6 for y and 72 for x in the direct variation equation:

(6 = 72k) / 72

6/72 = k

1/12 = k

Thus, the constant of proportionality (k) is 1/12.

Finding the value of y when x is 8:

Now, we can find the value of y when x is 8 by substituting 1/12 for k and 8 for x in the direct variation equation:

y = 1/12(8)

y = 8/12

y = 2/3

Therefore, y is 2/3 when x is 8.