The answer is in bold. I need to know HOW to do the problems. Thanks!

The following information relates to Snowbird Corporation: What is Snowbird's margin of safety? A) $62:500 B) $187, 500 C) $100:000 D) $212, 500| The following information relates to Zinc Corporation for last year: Sales at Zinc are expected to be $600,000 next year. Assuming no change in cost structure: this means that net operating income for next year should be: A) $30,000 B) $45,000 C)$50,000 D) $125,000