Someone help and please make sure it’s right

When i add money am i supposed to make it like this 7+12 or 7.00+12.00 because i got 19 dollars for my answer

Aremote-controlled boat can travel at 4 feet per second in calm water. the boat traveled 48 feet with the current, and then it traveled 16 feet against the current in the same amount of time. how fast is the current?

The police chief wants to know if the city’s african americans feel that the police are doing a good job. identify the management problem (i.e dependent variable) and identify the independent variable.