Direct Variation

[silverflamein]

P varies as the product of Q and R. If P is trebled ad Q is halved, what is the change in R.

Can someone solve this for me ?

[rijul007]

P varies as the product of Q and R
=> P = kQR [here k is a constant]

R = P/kQ

P' = 3*P
Q' = Q/2

R' = P'/kQ' = (3*P)/k(Q/2) = 6*P/kQ
R' = 6 * R

[shankar.ashwin]

P = k (Q*R)

R = P/kQ

I am assuming P is tripled so P(new) = 3P
And Q is halved Q(new)=Q/2

Substituting these new values we have,
R(new)=6P/kQ
(or) R(new)=6R

[Anurag@Gurome]

P varies as the product of Q and R. If P is trebled ad Q is halved, what is the change in R.

Can someone solve this for me ?

P is directly proportional to Q * R or P = k * QR, where k is any constant.
R = P/kQ
New R = 3P/(k * Q/2) = 6P/kQ = 6R

[GMATGuruNY]

P varies as the product of Q and R. If P is trebled ad Q is halved, what is the change in R.

Can someone solve this for me ?

Let P = 2, Q = 2, and R = 1.
P/(QR) = 2/(2*1) = 1.

P tripled = 3*2 = 6
Q halved = (1/2)*2 = 1.
Plugging new P and new Q into P/(QR) = 1, we get:
6/(1*R) = 1.
New R = 6.

Since old R = 1 and new R = 6, R is multiplied by a factor of 6.