The Final Prescription

If the demand loan component were set at 44 units, the overall burden of interest would have been (44 ´ 10% + 1 ´ 12% ´ 6/12 + 6 ´ 12% ´ 6/12) = 4.82 units.
On the other hand, if the demand loan component were set at 46 units, the overall interest burden would have been (46 ´ 10% + 4 ´ 12% ´ 6/12) = 4.84 units.
Obviously, the overall burden due to interest is minimized if the demand loan is set at 45 units.