Find the amount of time. i=$30, p=$500, r=3%

W-16=-12 solve each one step equation plz

Atourist boat is used for sightseeing in a nearby river. the boat travels 2.4 miles downstream and in the same amount of time, it travels 1.8 miles upstream. if the boat travels at an average speed of 21 miles per hour in the still water, find the current of the river.

Louis wants to give \$15 to kids who need school supplies. he also wants to buy a pair of shoes for \$39. how much money will he have to save for both?