Heather swam 5 kilometers against the current in the same amount of time it took her to swim 15 kilometers with the current. The rate of the current was 2 kilometers per hour. How fast would Heather swim if there were no current

4 km per hour

Step-by-step explanation:

Here we will assume the speed of Mary with no current be x km per hour

speed of current= 2 km/h 

Distance swam against current= 5km

Time is taken to swam against current=5 ÷ (x - 2)

distance swim with current = 15km

Time is taken to swim with current = 15 ÷ (x + 2)

Now

Given that  if the time taken in both instances are the same,

So, the equation will be

5 ÷ (x - 2) = 15 ÷ (x + 2)

After solving for x we will have

5 ÷ (x + 2) = 15 ÷ (x - 2)

5x + 10 = 15x - 30

10 + 30 = 15x - 5x

40 = 10x

x=40 ÷ 10

= 4 km per hour

option (b) is correct

step-by-step explanation:

to find the solution of this system, we need to convert it into reduced row-echelon form. we have,

after applying row operations r2 -> r2/2 and r3 -> r3/3, we get,

x=0

step-by-step explanation: