How do you solve word problems that deal with against the current/wind and such?

Question

The story problem is:

A ship crusing on a river can travel 135 miles in 15 hours when traveling against the current. When cruising with the current, the trip takes 10 hours. Find the speed of the ship in still water and the speed of the current.

I don't know where to start...

Answer 1

The logic is that the current makes the ship go faster if it is going with the current.

The current makes the ship go equally slower if it is going against the current.

The ship's speed in still water would be exactly halfway between the speeds with and against the current.

Speed against current = 135 miles/15 hours = 9 mi/h
Speed with current = 135 miles/10 hours = 13.4 mi/h
Average = speed in still water = (13.4 + 9)/2 = 11.2 mi/h

Answer 2

properly, all you ought to be attentive to is that speed is displacement divided via time. in case you're speaking approximately speed then, this is distance divided via time. displacement is only the a number of between very final and preliminary place. especially circumstances distance equals displacement, like on your question, yet comprehend displacent would properly be damaging or constructive. on your question the fee may well be 10ft/6seconds. the fee must be constructive or damaging looking on what you took your place on the roof suitable to be. you ought to declare that on the roof suitable, my place is 0 and and whilst it hits the floor, this is 10, hence that must be a great speed, or you ought to declare on the roof suitable, your place is 10 and on the floor is 0. There additionally are some formulae for speed (kinematics), that in case you have all the mandatory innovations, you will get the fee.