Question

HELP FOR BRAINIEST AND 50 POINTS

Answer 1

X - speed of the current
40+x - speed with current 
40-x - speed against current

t-time
(40+x)*t=100
(40-x)*t=60

           40t+xt=100
   +      40t-xt = 60
           80t      =160
                t      = 2

40t+xt=100,   
40*2+2x=100
80+2x=100
2x=100-80
2x=20
x=10 mi/h

10 mi/h speed of the current.

Answer 2

The answer is x/10mph Hope I helped!