Q. Two bodies having volumes V and 2V are suspended from the two arms of a common balance and they are found to balance each other. If larger body is immersed in oil(density $d_1$- 0.9 gm/$c{m}^3$) and the smaller body is immersed in an unknown liquid, then the balance remain in equilibrium. What is the density of unknown liquid?
A. 2.4 gm/$c{m}^3$
B. 1.8 gm/$c{m}^3$
C. 0.45 gm/$c{m}^3$
D. 2.7 gm/$c{m}^3$