Answer:
[tex]1 \dfrac{5}{7}\ mph[/tex]
Step-by-step explanation:
Let x mph be the current's rate.
Upstream:
Distance = 18 miles
Rate = 12 - x mph
Time [tex]=\dfrac{18}{12-x}[/tex] hours
Downstream:
Distance = 24 miles
Rate = 12 + x mph
Time [tex]=\dfrac{24}{12+x}[/tex] hours
Time is the same, so
[tex]\dfrac{18}{12-x}=\dfrac{24}{12+x}\\ \\18(12+x)=24(12-x)\\ \\216+18x=288-24x\\ \\18x+24x=288-216\\ \\42x=72\\ \\x=\dfrac{12}{7}=1 \dfrac{5}{7}\ mph[/tex]
