My professor tells me I'm not using the right formula for this problem. can someone please help me. The formula is not delt p = density x gravity x height

Question

The mercury manometer on the right and the pressure transducer on the left are both connected to a piston-driven pressure source filled with hydraulic oil (density = 880 kg/m^3). The bulbs connected to the transducer and the right side of the manometer are both evacuated (denisty = 0). Calculate pressures from the manometer reading.

hL (mm Oil) = 450
Manometer reading = 150
Transducer Output = 5.6 (mA)