Amotorboat takes 40 minutes to travel 20 miles downstream. the return trip takes 60 minutes. what is the speed of the current?

The current is 5 mph

Step-by-step explanation:

The current helps the boat going down stream and hinders going up so it adds to the speed downstream and subtracts going up.

speed downstream is 20miles/40minutes =1 mi per 2 min. Or 30 mph

Speed upstream is  

20 miles/ 60 minutes = 1 mile per 3minutes or 20 mph

So if the speed of the boat is the same (s) then downstream the boat travels  

S+c =30 mph and s-c =20mph upstream if c is tge current speed

So s=30-c and s=20+c  

So. 30-C=20+c

      10=2C

       5=C

The current is 5 mph

b

step-by-step explanation:

a difference is the result of subtraction. while each of these expressions has subtraction in it, a difference will be the result when subtraction is the last operation applied in the order of operations for the expression. this means subtraction must be outside of the parenthesis. only b has this.