Could use some help with explination on how to solve the following:

Flash Drive INC. produces flash drives. Each unit sells for $5.20

The per unit variable cost of manufacturing is $2.40

Monthly fixed costs of all operations are $156,000

Flash Drive anticipates an income tax rate of 30%

The (before tax) contribution margin per unit is?

In August, the company sold 5,000 more flash drives than planned.

What is the expected effect on after tax profit of selling the additionaldrives? Assume the company's normal sales level is profitable.

Calculate the (before tax) contribution margin ratio associated with

one flash drive.

In October, the company had sales that were $125,000

higher than planned. What is the effect on after tax profit related

to the additional sales? Assume the company's normal sales

level is profitable.