the speed of aboat in still water is 15km/hr it needs four more hours to travel 63km against the current of ariver than it need to travel down the river determine the speed of the current of the river

6 m/ s

Step-by-step explanation:

Let the speed of the boat in still water be represented by, Vb

Let speed of the river be Vr.

Let the time taken to travel downstream be t h

=> time taken to travel upstream = (t + 4) h.

___________________

1) While traveling upstream, the speed of the boat becomes equal to the difference of the speed of boat in still water and speed of the river, I.e.,

= Vb - Vr

= 15 - Vr

2) While traveling downstream, the speed of the boat becomes equal to the sum of of speed of boat in still water and speed of the river, I.e.,

= Vb + Vr

= 15 + Vr

___________________

Our golden formula:

Upstream:

Downstream:

solving for t so as to replace it in eqn. (i):

Placing it in eqn. (i)

Getting all variables to the LHS

combining like terms to get the following equation:

eliminating "-":

dividing the whole thing by 2:

factorising:

Either,

Vr = 6

or,

Vr = -37.5 m/ s

Since, it's the speed of the river we're talking about, it can't be negative.

Therefore,

Vr = 6 m/ s

option 2 is correct.

step-by-step explanation:

we are given two inequality equation

x+y> 5 and -3x+2y< -2

first we draw the graph of both function using t-table method

equation: x+y> 5

for x=0, y=5

for x=-5, y=0

table:

x   :   0     5

y   :   5     0

test point (0,0) , 0> 5

false

equation: -3x+2y< -2

for x=0, y=-1

for x=2, y=4

table:

x   :   0     2

y   : -1       4

test point (0,0) , 0< -2

true

now we draw the graph. see the attachment for graph.

common region would be solution set.

option 2 is correct.

step-by-step explanation:

when the line is solid:

when the line is dashed:

this > inequality sign means:

this < inequality sign means:

this > inequality sign means:

this < inequality sign means:

about the problem:

srry i'm not done ! i'll