$3.$ The Pew Internet and Technology Project finds that $91\%$ of gen X$-$ers $($adults born between $1965$ and $1980)$ use the internet and that $89\%$ of online gen X$-$ers say their use of the Internet is a good thing for them personally. Gen X$-$ers make up $20\mathrm{.}4\%$ of the U$.$S$.$ adult population.

a$.$ What percentage of gen X$-$ers are online and say the Internet is a good thing for them personally?

b$.$ What percentage of all U$.$S$.$ adults are gen X$-$ers, are online, and say their use of the Internet is a good thing for them personally?