Question

Please show the work for this is you need to solve it using systems of equations!!!

Answer 1

D=rt

c=speed of current
r=speed in still water
t=time
d=72

72=3(r+c)
72=4(r-c)
expand
divide top equation by 3 and bottom by 4

24=r+c
18=r-c
add them equations

42=2r+0c
42=2r
divide both sides by 2
21=r

sub back

18=r-c
18=21-c
minus 21 both sides
-3=-c
3=c

speed of current is 3
speed of ship is 21