Question

Suppose that y is directly proportional to x, and y = −16 when x = −2. What is the constant of proportionality?

A) −8
B) −
1
8
C) 1
8
D) 8

Answer 1

In the given expression the constant of proportionality is k = 8.

Explanation:

The quantity P is said to be directly proportional to Q if they vary in proportion to each other.

Here, P ∝ Q ⇔ P = kQ : k = Proportionality Constant

Now, here given y ∝ x and x = -2, y = -16

Now, y ∝ x ⇒ y = kxor, (-16) = k (-2) or, k = 16/2 = 8 ⇒ k = 8So, for k = 8, y ∝ x

Hence, in the given expression the constant of proportionality is k = 8.