Files can be downloaded using a broadband connection at a rate of bits per second $(50$ Mbps$).$ Using a fiber$-$optic cable, the download speed increases to $2$ Gbps$.$

a$.$ The pdf files for this text total about bytes $(65\mathrm{.}5$ MB$).$ There are $8$ bits in a byte. How long does it take to download these files using a broadband connection?

b$.$ How long does it take to download the files from part $($a$)$ using a fiber$-$optic cable?

c$.$ The Library of Congress digital collection totals about $74$ TB$.$ How long does it take to download these files using a broadband connection?

d$.$ How long does it take to download the files from part $($c$)$ using a fiber$-$optic cable?