<PRE><B>Question 178061</B>
A SPEEDBOAT COULD TRAVEL AT 5 TIMES THE SPEED OF A CURRENT. THUS, IT COULD
 TRAVEL 300 MILES DOWNRIVER IN 2 HOURS MORE THAN IT TOOK TO TRAVEL 150 MILES
 UPRIVER. WHAT WAS THE SPEED OF THE BOAT IN STILL WATER?
;
let x = boat speed in still water
:
given that current speed {{{1/5}}} boat speed, therefore we can say;
.2x = current speed
:
Then
1.2x = speed down stream
.8x = speed up stream
:
write a time equation time = {{{dist/speed}}}
downstream time = upstream time + 2 hrs
{{{300/1.2x}}} = {{{150/.8x}}} + 2
multiply equation by 2.4x to get rid of the denominators
2(300) = 3(150) + 2(2.4x)
:
600 = 450 + 4.8x
:
600 - 450 = 4.8x
:
x = {{{150/4.8}}}
x = 31.25 speed of boat in still water
:
:
Check solution in original equation
{{{300/1.2(31.25)}}} = {{{150/.8(31.25)}}} + 2
{{{300/37.5}}} = {{{150/25}}} + 2
 8 = 6 + 2</PRE>