Question

一道SAT数学的题A tugboar travels upstream form portA to portB in 8

Answer 1

设水流速度为x；船速为y

8(y-x) =6(x+y) =24;

所以：x+y =4；

y-x=3

x=0.5（mile/Hr)

y=3.5（miles/Hr)

所以水流速度为 0.4 英里/小时