Final answer:
To find q when p is 21 for inversely varying quantities, calculate the constant by multiplying the given values, then divide by the new p value. In this case, q equals 2.
Step-by-step explanation:
If p and q vary inversely, it means that the product of p and q is constant. We can describe this relationship with the formula pq = k, where k is a constant. Given that p is 3 when q is 14, we find the constant by multiplying them, giving us k = 3 * 14 = 42. To determine q when p is equal to 21, we set up the equation 21q = 42 and solve for q, which gives us q = 42 / 21 = 2.