Question

Q is directly proportional to √p Q = 21 when p = 9, the value of Q when p = 81 is *

Answer 1

Answer:

We get Q=63 when p=81

Option A is correct.

Step-by-step explanation:

We are given that $Q \propto \sqrt{p}$

We can write it as $Q=k\sqrt{p}$

Where k is constant of proportionality.

We are given Q = 21 when p = 9

Using this Q = 21 when p = 9 we can find value of k

$Q=k\sqrt{p}\\k=\frac{Q}{\sqrt{p} }\\k=\frac{21}{\sqrt{9} } \\k=\frac{21}{3}\\k=7$

So, we get constant of proportionality k = 7

Now, Finding the value of Q when p = 81

We are given p=81, k=7, we need to find Q

Using the equation $Q=k\sqrt{p}$ we can find value of Q.

$Q=k\sqrt{p}\\Q=7\sqrt{81}\\Q=7\times 9\\Q=63$

So, we get Q=63 when p=81

Option A is correct.