Convert 123 base 4 to base 10

Samantha swam upstream for some distance in one hour. she then swam downstream the same river for the same distance in only 12 minutes. if the river flows at 4 mph, how fast can samantha swim in still water?

Aschool puts on a play. the play costs $1,200 in expenses. the students charge $4.00 for tickets. there will be one performance of the play in an auditorium that seats 500 people. what is the domain of the function that shows the profit as a function of the number of tickets sold?  

Fatima plans to spend at least $15 and at most $20 dollars on sketch pads and pencils. if she buys 2 sketchpads, how many pemcils can she buy while staying in her price range? fatima can buy between and pencils. ? (type whole numbers. use ascending? order.)