To add some realism to this game, i thought it would be a good idea to double, triple and so on for the number of buildings being built. For example, a hospital is being built in 6 days, the player wants to build something else, the result of this decision is the increase in time required to build the hospital up to 12 days, 18 days if a third structure is chosen.
This shows that the people involved in construction are splitting up their resources add adjusting to the changes chosen by the player.