Dana's Electronic Parts $($DEP$)$ is trying to decide whether or not to introduce a new model. If they do introduce it$,$ there will be additional fixed costs of $$400,000$ per year. The variable costs have been estimated to be $$20$ per part.

a$)$ If DEP sells the new model for $$30$ per unit, how many must they sell to break even?

b$)$ If DEP sells $70,000$ of the new model at the $$30$ price, what will the contribution to profit be$?$