Question 109325
1) 105/(18+x)=75/(18-x) now cross multiply
75(18+x)=105(18-x)
1350+75x=1890-105x
75x+105x=1890-1350
180x=540
x=540/180
x=3 kh. is the speed of the current.
2) x*2x/(x+2x)=16
2x*2/3x=16 now cross multiply
16*3x=2x^2
2x^2-48x=0
2x(x-24)=0
x=24 hours for the larger pipe to fill the tank.
2*24=48 hours for the smaller pipe.
proof
24*48/(24+48)=16
1152/72=16
72*16=1152
1152=1152