Question

If p and q vary inversely and p is 2 when q is 21, determine q when p is equal to 6.

Answer 1

Answer:

$q = 7$

Step-by-step explanation:

Given

$p\ \alpha\ \frac{1}{q}$ --- inverse variation

$p =2; q = 21$

Required

Find q when $p = 6$

$p\ \alpha\ \frac{1}{q}$

This becomes

$p = \frac{k}{q}$

Where k is the constant of variation.

Make k the subject

$k = p * q$

Substitute $p =2; q = 21$

$k = 2 * 21$

$k =42$

When $p = 6$, we have:

$p = \frac{k}{q}$

$6 = \frac{42}{q}$

Make q the subject

$q = \frac{42}{6}$

$q = 7$