You don't run 10/2 or 12/2 in conduit. That type of wire already has its own sheath on it.

Buy 10 foot lengths of PVC plastic pipe that is designed for underground burial and then pull 2 runs of single strand #10, 2 runs of #12 single strand and 1 run of GREEN #10 single strand into the ONE INCH diameter PVC conduit at the same time. Now if either of the twin runs is for 240 volt, then make those runs using red coloured wire. If either or both runs are 120 volt, then use one black and one white.

You must have four conductors plus the green ground wire. The two circuits can share the single ground line but you must have separate white (neutral) wires for each circuit.

Use an appropriate size of circuit breaker for the intended load. You have a long run here of 150 feet. The 12 gauge wire will support 15 amps on a run this long. On runs 100 feet or less, it will support a 20 amp load.

The 10 guage would normally handle a 30 amp load but considering the distance, 20 amp is more realistic. The above is based upon 120 volt operation. Switching to 240 volts allows you to double the amperage.

Do not try to use too small of a conduit to save money. Wires generate heat when under load. You don't want these wires jammed together against one another. Larger conduit makes it easier to pull the wires in. Keep your conduit run as straight as possible. Try to use 45 degree bends instead of 90's. To get a 90, use two 45's separated by a couple of feet of conduit whenever possible.

Stranded wire pulls much easier than solid wire does but it costs a bit more.

Your conduit should be buried at least 2 feet below grade in open areas and 3 feet below if it runs under a driveway. Make sure that you talk to someone such as an electrician before undertaking this job. It's cheaper to do the work RIGHT the first time then it is to redo it later on when you find out that you did not do it right.

Kompressor: You Should Have Been A Hydraulic Enginneer , Fluid Frictional Loss = 2 % for a 45 Degree Elbow (Short Raduis) and 5 % for a 90 Degree (Short Raduis) Elbow ! Don't ask me about Hydro Residental Codes . From what I can see you have also have a Civil Engineering Degree around the Corner at least 3-5 ' Below Grade for Frost Line Specifications in the Northern States and Provinces ! Good Post Bro !!!

Why not just use Tek Cable ?

Yikes, mr. kompressor sounds like answer man.

Just to add, around here, if it's a single cable, they snake it through plastic well pipe, then bury it in a few inches of sand or stone dust. Yellow "Caution" tape goes on top of that, then backfill the trench.