Fourth grade level. use mental math to find 7x53

3x + 4y = 5 x- 3y = -7 solve by substitution

Need same math paper but the back now i hope your able to read it cleary i need with hw

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?