A varies directly with difference of B and C. B varies directly with M and C varies directly with √M. If M = 4 then A = 18 and when M = 9 then A = 42. Find the value of M when A = 4.
A varies directly with difference of B and C. B varies directly with M and C varies directly with √M. If M = 4 then A = 18 and when M = 9 then A = 42. Find the value of M when A = 4. Correct Answer 1
Given:
⇒ A = K(B - C)......(K is a constant)
⇒ B = k(M)......(k is a constant)
⇒ C = n(√M)......(n is a constant)
Calculation:
⇒ A = K(kM - √M)
⇒ A = (PM - Q√M)......( P = Kk and Q = Kn)
Then,
⇒ 18 = 4P - 2Q
⇒ 42 = 9P - 3Q
Solving,
⇒ P = 5 and Q = 1
Then,
⇒ 4 = 5M - 1 × √M
⇒ M = 1......(by trial and error)
∴ Required value of M = 1
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Feb 20, 2025