let's set up an equation
4x=24
solve normally:
x=6
so the expression is 4x=24 and she can have 6 kids in each group
Try y=-2x-3 (I think that should be it)
Answer:

Step-by-step explanation:
The systems of equations are
Let us assume the rate of the current be c
Now actual speed against the current is (15 - c)
And, the actual speed with the current is (15 + c)
Here we applied the time formula i.e. distance by speed
Also the upstream time - downstream time = 4
Now the equations are

He would receive $5.63, not including tax