Julianna Abdallah owns and operates FirstCakes, a bakery that creates personalized birthday cakes for a child's first birthday. The cakes, which sell for $56 and feature an edible picture of the child, are shipped throughout the country. A typical month's results are as follows:

Sales revenue$864,640

Variable expenses648,480

Contribution margin216,160

Fixed expenses102,340

Operating income$113,820

How many cakes will Julianna Abdallah have to sell if she wants to earn $136,458 in operating income each month?

can you please walk me through the steps to solve this problem.