Question

A motorboat traveling a distance of 225 miles in 5 hours while traveling with the current. Against the current, the same trip took 9 hours. Find the rate of the boat in calm water and the rate of the current.
rate of boat mph
rate of current mph

Answer 1

Let c=current speed, and
b=boat speed in still water.

Speed with current = 225/5=45 mph
Speed against current = 225/9=25 mph,

Set up equations:
b+c=45
b-c=25

Solve for b and c.

By the way, when you know the sum and difference of two variables, the variable with the larger value equals (sum+difference)/2 and the variable with the smaller value is (sum-difference)/2.
No need to solve for a system of equations.