Pumps \(A, B,\) and \(C\) operate at their respective constant rates. Pumps \(A\) and \(B,\) operating simultaneously,

[M7MBA]

Pumps \(A, B,\) and \(C\) operate at their respective constant rates. Pumps \(A\) and \(B,\) operating simultaneously, can fill a certain tank in \(\dfrac65\) hours; pumps \(A\) and \(C,\) operating simultaneously, can fill the tank in \(\dfrac32\) hours; and pumps \(B\) and \(C,\) operating simultaneously, can fill the tank in \(2\) hours. How many hours does it take pumps \(A, B,\) and \(C,\) operating simultaneously, to fill the tank?

A. \(\dfrac13\)

B. \(\dfrac12\)

C. \(\dfrac14\)

D. \(1\)

E. \(\dfrac56\)

Answer: D

Source: GMAT Prep