If P varies inversely as V and V varies directly as R2, find the relationship between P and R given that R = 7 when P = 2

A.

P = 98R2

B.

PR2 = 98

C.

P = \(\frac{1}{98R2

D.

P = \(\frac{PR2}{98}\)

Correct answer is B

P = \(\frac{1}{v}\) and vR2 = P = \(\frac{k}{v}\)......(i)

and v KR2 .......(ii)

(where k is constant)

Subst. for v in equation (i) = p = \(\frac{1^2}{KR}\).....(ii)

when r = 7, p = 2

2 = \(\frac{k}{7^2}\)

k = 2 x 49

= 98

Subt. foe k in ....(iii)

P = \(\frac{98}{R^2}\)

PR2 = 98