I need help with following question

Genetic information in all living things is coded as DNA molecules. A DNA molecule

is a linear sequence of the four basic nucleotides: A, C, G, and T. The human genome

contains approximately 3 109 nucleotides in the form of about 30,000 genes. What

is the total information capacity (in bits) of the human genome? What is the maximum

information capacity (in bits) of the average gene?

The answer is 200,000 bits per gene but I don't know how to get this answer

PLease help

Thanks