Find the measure of the arc or angle indicate. someone help me plz

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?

Write an expression that has three terms and simplifies to 4x - 7. identify the coefficient(s) and constant(s) in your expression

Find the number of liters in 12.8 gal of gasoline. round to the nearest hundredths