# If the Yield (Y) of the cosnumers change, does the $Q_{D}$ remain parallel?

Because we have a change in Yield (Y) which is a factor of demand, we have a move in the $$Q_D$$. However, not all changes in the Yield affect the $$Q_D$$ the same way right? For example, if we know that $$E_Y=2$$ and that $$ΔΥ/Υ=20$$%, from the elasticity we can compute $$ΔQ/Q= 40$$%, so $$Q_{D'}=1,4Q_D$$ so it's not parallel. For the change in $$Q_{D'}$$ to be parallel, however, will the exercise disclose that $$Q_D$$ and $$Q_{D'}$$ are parallel, or that the demand changes for some constant, e.g. $$Q_{D'}= Q_D+30$$. Am I right? Thanks a lot!