Question

A motorboat takes
5
hours to travel
100mi
going upstream. The return trip takes
2
hours going downstream. What is the rate of the boat in still water and what is the rate of the current?

Answer 1

is this algebra ?

Answer 2

i think

Answer 3

Do you know if you are in a boat and the boat just "floats" , it will move downstream at the rate of the current ?

Answer 4

Yes I know how to calculate speed I don't know how to calculate the rate of the current

Answer 5

Do you know that
rate * time = distance
?

Answer 6

yes

Answer 7

to do the problem, let
x= rate of the boat
y = rate of the current
when the boat goes downstream, it's total rate is x+y
any idea what the rate is going upstream ?

Answer 8

no

Answer 9

if you rowed upstream (instead of in still water), would you go faster or slower compared to still water ?

Answer 10

slower

Answer 11

if the current carried you backward at a rate of y, and you rowed forward at a rate of x
how do you show how fast you are going (compared to still water)
want to guess ?

Answer 12

the difference of the rates?

Answer 13

yes

Answer 14

how do you show a difference ?

Answer 15

dividing distance by time?

Answer 16

difference is shown by subtracting

Answer 17

i thought you meant something else, sorry

Answer 18

hopefully it make sense: the boat moves upstream at a rate of (x-y)
and it goes downstream at a rate of (x+y)

Answer 19

A motorboat takes 5 hours to travel 100 miles going upstream.
can you write a "rate * time = distance" equation
using a rate (going upstream), an unknown time "t" and a distance 100 miles?

Answer 20

t x 5 = 100

t x 2 = 100

Answer 21

5 hours to travel 100 miles going upstream.

time is 5
distance is 100
so it is
rate * 5 = 100

but what rate should we use ? remember we are using x= rate of boat and y=rate of the current. how fast does the boat go upstream ?

Answer 22

20mph upstream 50mph downstream

Answer 23

the boat moves upstream at a rate of (x-y)

Answer 24

I forgot what x and y were

Answer 25

distance and time?

Answer 26

x is how fast the boat moves in still water
y is how fast the current moves
(x-y) is how fast the boat can go upstream

Answer 27

how do you find the current speed

Answer 28

we write two equations
5(x-y)= 100
and
2(x+y)= 100

and solve for x and y

Answer 29

20 and 50

Answer 30

@phi