DO IT$?5-5($LO $4,5),$ AP Presto Company makes radios that sell for $$30$ each. For the coming year, management expects fixed costs to total $$220,000$ and unit variable costs to be $$18.$

a$.$ Compute the break$-$even point in sales dollars using the contribution margin $($CM$)$ ratio.

b$.$ Compute the margin of safety ratio assuming actual sales are $$800,000.$

c$.$ Compute the sales dollars required to earn net income of $$140,000.$