The value of P varies directly as the square of Q. When Q is 4, then P is 48. What is the value of Q when P is 243?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 9.
The value of P varies directly from the square of Q.
P ∝ Q2
⇒ P = K × Q2
When Q is 4, then P is 48.
⇒ 48 = K × 42
⇒ 48 = K × 16
⇒ K = 3
Value of Q when P is 243.
⇒ P = K × Q2
⇒ 243 = 3Q2
⇒ 81 = Q2
⇒ Q = 9