>
> Sorry, it's driving me crazy. Can anyone help with below.
> The equations I came up with don't seem to be right.
>
> Thanks,
> Joanna
> ___________________________________________
>
> Boat can travel 5 times speed of current.
> It can travel 375 miles downriver in 1 hour more than it
> takes to travel 225 miles upriver. What is speed of boat
> in still water?
>
> r = speed of current
> t = time
>
> 375 = 6r ( t + 1)
> 275 = 4r (t)
Slip of the pencil; the second equation should be 225 = 4rt (this is probably where your problem comes from)
375 = 6r(t + 1) 225 = 4rt
multiply both sides of equation 1 by 2, multiply both sides of equation 2 by 3
750 = 12rt + 12r 675 = 12rt
subtract equation 2 from equation 1
75 = 12r
75/12 = r = 6.25
going back to equation 2
225 = 4rt = (4 * 6.25) t = 25t
225/25 = t = 9
check:
(6 * 6.25) * (9 + 1) = 37.5 * 10 = 375 OK 4 * 6.25 * 9 = 225 OK
Yours WDK - WKiernan at ij.net