Question

_

Answer 1

let speed of boat in still water be 'x' mph
and speed of water be 'y' mph

going downstream,
the boat will go with the speed of x+y

does this makes sense ?

Answer 2

when the boat goes upstream
the water will oppose the boat

hence in upstream, the boat will move with 'x-y' speed

Answer 3

if you get these, rest of the problem is easy to solve, just plugging in and solving simultaneous equation algebraically :)

Answer 4

about what ?

Answer 5

thats later, first read what i posted and make sure you understand...you gonna use that a lot many times later

Answer 6

how did u get speed of water as 3 ?

Answer 7

you must also know
\(\Large speed = distance/ time\)

Answer 8

and what did you get that 40 as ??
speed of ?

Answer 9

no, that why the explanation was given before

its the speed of DOWNSTREAM

which is \(\huge x+y\)

which is speed of boat in still water + speed of water

Answer 10

return journey is upstream,
so the speed you get there will be upstream speed
which will be
x-y

Answer 11

the question asks for speed of boat in still water = x = ...?

Answer 12

we have

x+y =40

and what did u get x-y as ?

or you didn't calculate that yet ?

Answer 13

-_-

read my first 2 comments again
and again

Answer 14

and again :P

Answer 15

DOWNSTREAM:

distance = 120
time = 3
speed = x+y

Answer 16

UPSTREAM:

distance = 120
time = 4
speed = x-y

Answer 17

speed = diatance /time

DOWNSTREAM :

x+y = 120/3 = 40

Answer 18

UPSTREAM:
x-y =120/4 = 30

Answer 19

now you have

x+y =40
x-y=30

can you get x and y

Answer 20

is it ?

or since you're adding

2x =70 ?

Answer 21

35mph
\(\huge \checkmark\)

Answer 22

can u solve similar type of questions ?

Answer 23

practice, you'll get it :)