One faucet fills a barrel in 6 minutes while an another one - in 12 minutes. if both faucets are turned on for one minute, what fraction of the barrel will be left to fill? need answer asap!

Sam is a waiter at a local restaurant where he earns wages of $5 per hour sam figures that he also eams about $3 in tips for each person he serves sam works 6 hours on a particular day. if n represents the number of people sam serves that day, which of the following functions could sam use to figure ehis total earings for the do o a. en) = 30 o b. en) = 5n+ 18