Ng Corporation produces and sells only one product; its selling price is $100 and its variable cost is $80 per unit. The company's monthly fixed expense is $20,000. Required: 1. Using the equation method, determine the unit sales that are required to earn a target profit before tax of $3,000 Un sales units 2. Using the formule method, determine for the dollar sales that are required to earn a target profit before tax of $4,000. 2. Using the formula method, determine for the dollar sales that are required to earn a target profit before tax of $4.000. Dollar sales 3. Using the formula method, calculate the number of units that need to be sold to earn an after-tax income of $6,000, assuming a tax rate of 25%. Number of units units